diff --git a/pkg/loop/internal/pb/chain_reader.pb.go b/pkg/loop/internal/pb/chain_reader.pb.go
index 4f7b84491..4f56656da 100644
--- a/pkg/loop/internal/pb/chain_reader.pb.go
+++ b/pkg/loop/internal/pb/chain_reader.pb.go
@@ -1500,7 +1500,7 @@ type Block struct {
 	sizeCache     protoimpl.SizeCache
 	unknownFields protoimpl.UnknownFields
 
-	BlockNumber uint64             `protobuf:"varint,1,opt,name=block_number,json=blockNumber,proto3" json:"block_number,omitempty"`
+	BlockNumber string             `protobuf:"bytes,1,opt,name=block_number,json=blockNumber,proto3" json:"block_number,omitempty"`
 	Operator    ComparisonOperator `protobuf:"varint,2,opt,name=operator,proto3,enum=loop.ComparisonOperator" json:"operator,omitempty"`
 }
 
@@ -1536,11 +1536,11 @@ func (*Block) Descriptor() ([]byte, []int) {
 	return file_chain_reader_proto_rawDescGZIP(), []int{21}
 }
 
-func (x *Block) GetBlockNumber() uint64 {
+func (x *Block) GetBlockNumber() string {
 	if x != nil {
 		return x.BlockNumber
 	}
-	return 0
+	return ""
 }
 
 func (x *Block) GetOperator() ComparisonOperator {
@@ -2101,7 +2101,7 @@ var file_chain_reader_proto_rawDesc = []byte{
 	0x72, 0x52, 0x10, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x43, 0x6f, 0x6d, 0x70, 0x61, 0x72, 0x61, 0x74,
 	0x6f, 0x72, 0x73, 0x22, 0x60, 0x0a, 0x05, 0x42, 0x6c, 0x6f, 0x63, 0x6b, 0x12, 0x21, 0x0a, 0x0c,
 	0x62, 0x6c, 0x6f, 0x63, 0x6b, 0x5f, 0x6e, 0x75, 0x6d, 0x62, 0x65, 0x72, 0x18, 0x01, 0x20, 0x01,
-	0x28, 0x04, 0x52, 0x0b, 0x62, 0x6c, 0x6f, 0x63, 0x6b, 0x4e, 0x75, 0x6d, 0x62, 0x65, 0x72, 0x12,
+	0x28, 0x09, 0x52, 0x0b, 0x62, 0x6c, 0x6f, 0x63, 0x6b, 0x4e, 0x75, 0x6d, 0x62, 0x65, 0x72, 0x12,
 	0x34, 0x0a, 0x08, 0x6f, 0x70, 0x65, 0x72, 0x61, 0x74, 0x6f, 0x72, 0x18, 0x02, 0x20, 0x01, 0x28,
 	0x0e, 0x32, 0x18, 0x2e, 0x6c, 0x6f, 0x6f, 0x70, 0x2e, 0x43, 0x6f, 0x6d, 0x70, 0x61, 0x72, 0x69,
 	0x73, 0x6f, 0x6e, 0x4f, 0x70, 0x65, 0x72, 0x61, 0x74, 0x6f, 0x72, 0x52, 0x08, 0x6f, 0x70, 0x65,
diff --git a/pkg/loop/internal/pb/chain_reader.proto b/pkg/loop/internal/pb/chain_reader.proto
index 2c61141e8..c84e12620 100644
--- a/pkg/loop/internal/pb/chain_reader.proto
+++ b/pkg/loop/internal/pb/chain_reader.proto
@@ -151,7 +151,7 @@ message Comparator  {
 }
 
 message Block{
-  uint64 block_number = 1;
+  string block_number = 1;
   ComparisonOperator operator = 2;
 }
 
diff --git a/pkg/loop/internal/relayer/pluginprovider/chainreader/helper_test.go b/pkg/loop/internal/relayer/pluginprovider/chainreader/helper_test.go
index 6928e0e50..a38b87eb0 100644
--- a/pkg/loop/internal/relayer/pluginprovider/chainreader/helper_test.go
+++ b/pkg/loop/internal/relayer/pluginprovider/chainreader/helper_test.go
@@ -106,7 +106,7 @@ func generateQueryFilterTestCases(t *testing.T) []query.KeyFilter {
 
 	primitiveExpressions := []query.Expression{query.TxHash("txHash")}
 	for _, op := range operatorValues {
-		primitiveExpressions = append(primitiveExpressions, query.Block(123, op))
+		primitiveExpressions = append(primitiveExpressions, query.Block("123", op))
 		primitiveExpressions = append(primitiveExpressions, query.Timestamp(123, op))
 
 		var valueComparators []primitives.ValueComparator
diff --git a/pkg/types/query/primitives/primitives.go b/pkg/types/query/primitives/primitives.go
index c18b608c5..34d26d352 100644
--- a/pkg/types/query/primitives/primitives.go
+++ b/pkg/types/query/primitives/primitives.go
@@ -42,7 +42,7 @@ func (f *Comparator) Accept(visitor Visitor) {
 
 // Block is a primitive of KeyFilter that filters search in comparison to block number.
 type Block struct {
-	Block    uint64
+	Block    string
 	Operator ComparisonOperator
 }
 
diff --git a/pkg/types/query/query.go b/pkg/types/query/query.go
index 1246a0bd7..129af6760 100644
--- a/pkg/types/query/query.go
+++ b/pkg/types/query/query.go
@@ -57,7 +57,7 @@ func Comparator(name string, valueComparators ...primitives.ValueComparator) Exp
 	return Expression{Primitive: &primitives.Comparator{Name: name, ValueComparators: valueComparators}}
 }
 
-func Block(block uint64, operator primitives.ComparisonOperator) Expression {
+func Block(block string, operator primitives.ComparisonOperator) Expression {
 	return Expression{
 		Primitive: &primitives.Block{Block: block, Operator: operator},
 	}
diff --git a/pkg/types/query/query_test.go b/pkg/types/query/query_test.go
index 7773c36a5..3ed3e4f1b 100644
--- a/pkg/types/query/query_test.go
+++ b/pkg/types/query/query_test.go
@@ -39,20 +39,20 @@ func Test_AndOrEdgeCases(t *testing.T) {
 		},
 		{
 			name:        "And with multiple expressions",
-			expressions: []Expression{TxHash("txHash"), Block(123, primitives.Eq)},
+			expressions: []Expression{TxHash("txHash"), Block("123", primitives.Eq)},
 			constructor: And,
 			expected: And(
 				TxHash("txHash"),
-				Block(123, primitives.Eq),
+				Block("123", primitives.Eq),
 			),
 		},
 		{
 			name:        "Or with multiple expressions",
-			expressions: []Expression{TxHash("txHash"), Block(123, primitives.Eq)},
+			expressions: []Expression{TxHash("txHash"), Block("123", primitives.Eq)},
 			constructor: Or,
 			expected: Or(
 				TxHash("txHash"),
-				Block(123, primitives.Eq),
+				Block("123", primitives.Eq),
 			),
 		},
 	}