diff --git a/R/check_args_default.R b/R/check_args_default.R
index 0c34e1a2..25091ef2 100644
--- a/R/check_args_default.R
+++ b/R/check_args_default.R
@@ -65,70 +65,22 @@
     compartments = compartments_default
   )
 
-  # add null intervention and vaccination if these are missing
-  # if not missing, check that they conform to expectations
-  # add null rate_intervention if this is missing
-  # if not missing, check that it conforms to expectations
-  if (is.null(mod_args[["intervention"]])) {
-    # add dummy list elements named "contacts", and one named "transmissibility"
-    mod_args[["intervention"]] <- list(
-      contacts = no_contacts_intervention(
-        mod_args[["population"]]
-      ),
-      transmissibility = no_rate_intervention()
-    )
-  } else {
-    # check intervention list names
-    checkmate::assert_names(
-      names(mod_args[["intervention"]]),
-      subset.of = c(
-        "transmissibility", "infectiousness_rate", "recovery_rate", "contacts"
-      )
-    )
-    # if a contacts intervention is passed, check it
-    if ("contacts" %in% names(mod_args[["intervention"]])) {
-      # check the intervention on contacts
-      assert_intervention(
-        mod_args[["intervention"]][["contacts"]], "contacts",
-        mod_args[["population"]]
-      )
-    } else {
-      # if not contacts intervention is passed, add a dummy one
-      mod_args[["intervention"]]$contacts <- no_contacts_intervention(
-        mod_args[["population"]]
-      )
-    }
-
-    # if there is only an intervention on contacts, add a dummy intervention
-    # on the transmissibility
-    if (identical(names(mod_args[["intervention"]]), "contacts")) {
-      mod_args[["intervention"]]$transmissibility <- no_rate_intervention()
-    }
-  }
+  assert_intervention(
+    mod_args[["intervention"]][["contacts"]], "contacts",
+    mod_args[["population"]]
+  )
 
-  if (is.null(mod_args[["vaccination"]])) {
-    mod_args[["vaccination"]] <- no_vaccination(
-      mod_args[["population"]]
-    )
-  } else {
-    # default model only supports a single dose vaccination
-    assert_vaccination(
-      mod_args[["vaccination"]],
-      doses = 1L, mod_args[["population"]]
-    )
-  }
+  assert_vaccination(
+    mod_args[["vaccination"]],
+    doses = 1L, mod_args[["population"]]
+  )
 
-  # handle time dependence if not present, and check targets if present
-  if (is.null(mod_args[["time_dependence"]])) {
-    mod_args[["time_dependence"]] <- no_time_dependence()
-  } else {
-    checkmate::assert_names(
-      names(mod_args[["time_dependence"]]),
-      subset.of = c(
-        "transmissibility", "infectiousness_rate", "recovery_rate"
-      )
+  checkmate::assert_names(
+    names(mod_args[["time_dependence"]]),
+    subset.of = c(
+      "transmissibility", "infectiousness_rate", "recovery_rate"
     )
-  }
+  )
 
   # return arguments invisibly
   invisible(mod_args)
diff --git a/R/model_default.R b/R/model_default.R
index 5b2c4089..e06e1c6b 100644
--- a/R/model_default.R
+++ b/R/model_default.R
@@ -102,9 +102,12 @@ model_default_cpp <- function(population,
                               transmissibility = 1.3 / 7.0,
                               infectiousness_rate = 1.0 / 2.0,
                               recovery_rate = 1.0 / 7.0,
-                              intervention = NULL,
-                              vaccination = NULL,
-                              time_dependence = NULL,
+                              intervention = list(
+                                contacts = no_contacts_intervention(population),
+                                transmissibility = no_rate_intervention()
+                              ),
+                              vaccination = no_vaccination(population),
+                              time_dependence = no_time_dependence(),
                               time_end = 100,
                               increment = 1) {
   # check class on required inputs
@@ -116,12 +119,12 @@ model_default_cpp <- function(population,
 
   # all intervention sub-classes pass check for intervention superclass
   # note intervention and time-dependence targets are checked in dedicated fn
-  checkmate::assert_list(
-    intervention,
-    types = "intervention", null.ok = TRUE,
-    any.missing = FALSE, names = "unique"
-  )
-  checkmate::assert_class(vaccination, "vaccination", null.ok = TRUE)
+  # checkmate::assert_list(
+  #   intervention,
+  #   types = "intervention", null.ok = TRUE,
+  #   any.missing = FALSE, names = "unique"
+  # )
+  checkmate::assert_class(vaccination, "vaccination")
 
   # check that time-dependence functions are passed as a list with at least the
   # arguments `time` and `x`
@@ -265,9 +268,12 @@ model_default_r <- function(population,
                             transmissibility = 1.3 / 7.0,
                             infectiousness_rate = 1.0 / 2.0,
                             recovery_rate = 1.0 / 7.0,
-                            intervention = NULL,
-                            vaccination = NULL,
-                            time_dependence = NULL,
+                            intervention = list(
+                              contacts = no_contacts_intervention(population),
+                              transmissibility = no_rate_intervention()
+                            ),
+                            vaccination = no_vaccination(population),
+                            time_dependence = no_time_dependence(),
                             time_end = 100,
                             increment = 1) {
   # check class on required inputs
diff --git a/tests/testthat/test-input_checking_intervention.R b/tests/testthat/test-input_checking_intervention.R
index b5fb43fc..6c6d92f1 100644
--- a/tests/testthat/test-input_checking_intervention.R
+++ b/tests/testthat/test-input_checking_intervention.R
@@ -31,6 +31,20 @@ test_intervention_bad <- intervention(
   reduction = 0.2
 )
 
+test_rate_intervention <- intervention(
+  type = "rate",
+  time_begin = 60,
+  time_end = 100,
+  reduction = 0.2
+)
+test_bad_rate_intervention <- intervention(
+  type = "rate",
+  time_begin = 60,
+  time_end = 100,
+  reduction = matrix(0.2)
+)
+
+
 test_that("Interventions are checked correctly", {
   # check for no conditions on a well formed intervention
   expect_no_condition(
@@ -46,6 +60,21 @@ test_that("Interventions are checked correctly", {
       test_intervention # with population missing
     )
   )
+
+  expect_no_condition(
+    assert_intervention(
+      type = "rate",
+      test_rate_intervention # with population missing
+    )
+  )
+  expect_no_condition(
+    assert_intervention(
+      type = "rate",
+      test_rate_intervention,
+      population = test_population
+    )
+  )
+
   expect_error(
     assert_intervention(
       test_intervention,
@@ -62,4 +91,11 @@ test_that("Interventions are checked correctly", {
       population = test_population
     )
   )
+  expect_error(
+    assert_intervention(
+      test_bad_rate_intervention,
+      "contacts",
+      population = test_population
+    )
+  )
 })
diff --git a/vignettes/rate_interventions.Rmd b/vignettes/rate_interventions.Rmd
index 43904e6d..0a580c78 100644
--- a/vignettes/rate_interventions.Rmd
+++ b/vignettes/rate_interventions.Rmd
@@ -130,7 +130,10 @@ data <- model_default_cpp(
 # with a mask mandate
 data_masks <- model_default_cpp(
   population = uk_population,
-  intervention = list(transmissibility = mask_mandate),
+  intervention = list(
+    transmissibility = mask_mandate,
+    contacts = no_contacts_intervention(uk_population)
+  ),
   time_end = 200, increment = 1.0
 )
 ```