diff --git a/poseidon/export_test_vectors/src/vectors.rs b/poseidon/export_test_vectors/src/vectors.rs
index b8feddeeb8..ee047890cf 100644
--- a/poseidon/export_test_vectors/src/vectors.rs
+++ b/poseidon/export_test_vectors/src/vectors.rs
@@ -1,5 +1,5 @@
 use super::{Mode, ParamType};
-use ark_ff::UniformRand as _;
+use ark_ff::{PrimeField, UniformRand as _};
 use ark_serialize::CanonicalSerialize as _;
 use mina_curves::pasta::Fp;
 use mina_poseidon::{
@@ -78,7 +78,7 @@ pub fn generate(mode: Mode, param_type: ParamType) -> TestVectors {
             .into_iter()
             .map(|elem| {
                 let mut input_bytes = vec![];
-                elem.0
+                elem.into_bigint()
                     .serialize_uncompressed(&mut input_bytes)
                     .expect("canonical serialiation should work");
 
@@ -90,7 +90,7 @@ pub fn generate(mode: Mode, param_type: ParamType) -> TestVectors {
             .collect();
         let mut output_bytes = vec![];
         output
-            .0
+            .into_bigint()
             .serialize_uncompressed(&mut output_bytes)
             .expect("canonical serialization should work");
 
@@ -112,3 +112,116 @@ pub fn generate(mode: Mode, param_type: ParamType) -> TestVectors {
 
     TestVectors { name, test_vectors }
 }
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+
+    #[test]
+    fn poseidon_test_vectors_regression() {
+        use mina_poseidon::pasta;
+        let mut rng = &mut rand::rngs::StdRng::from_seed([0u8; 32]);
+
+        // Values are generated w.r.t. the following commit:
+        // 1494cf973d40fb276465929eb7db1952c5de7bdc
+        // (that still uses arkworks 0.3.0)
+
+        let expected_output_bytes_legacy = [
+            [
+                27, 50, 81, 182, 145, 45, 130, 237, 199, 139, 187, 10, 92, 136, 240, 198, 253, 225,
+                120, 27, 195, 230, 84, 18, 63, 166, 134, 42, 76, 99, 230, 23,
+            ],
+            [
+                233, 146, 98, 4, 142, 113, 119, 69, 253, 205, 96, 42, 59, 82, 126, 158, 124, 46,
+                91, 165, 137, 65, 88, 8, 78, 47, 46, 44, 177, 66, 100, 61,
+            ],
+            [
+                31, 143, 157, 47, 185, 84, 125, 2, 84, 161, 192, 39, 31, 244, 0, 66, 165, 153, 39,
+                232, 47, 208, 151, 215, 250, 114, 63, 133, 81, 232, 194, 58,
+            ],
+            [
+                153, 120, 16, 250, 143, 51, 135, 158, 104, 156, 128, 128, 33, 215, 241, 207, 48,
+                47, 48, 240, 7, 87, 84, 228, 61, 194, 247, 93, 118, 187, 57, 32,
+            ],
+            [
+                249, 48, 174, 91, 239, 32, 152, 227, 183, 25, 73, 233, 135, 140, 175, 86, 89, 137,
+                127, 59, 158, 177, 113, 31, 41, 106, 153, 207, 183, 64, 236, 63,
+            ],
+            [
+                70, 27, 110, 192, 143, 211, 169, 195, 112, 51, 239, 212, 9, 207, 84, 132, 147, 176,
+                3, 178, 245, 0, 219, 132, 93, 93, 31, 210, 255, 206, 27, 2,
+            ],
+        ];
+
+        let expected_output_bytes_kimchi = [
+            [
+                168, 235, 158, 224, 243, 0, 70, 48, 138, 187, 250, 93, 32, 175, 115, 200, 27, 189,
+                171, 194, 91, 69, 151, 133, 2, 77, 4, 82, 40, 190, 173, 47,
+            ],
+            [
+                194, 127, 92, 204, 27, 156, 169, 110, 191, 207, 34, 111, 254, 28, 202, 241, 89,
+                145, 245, 226, 223, 247, 32, 48, 223, 109, 141, 29, 230, 181, 28, 13,
+            ],
+            [
+                238, 26, 57, 207, 87, 2, 255, 206, 108, 78, 212, 92, 105, 193, 255, 227, 103, 185,
+                123, 134, 79, 154, 104, 138, 78, 128, 170, 185, 149, 74, 14, 10,
+            ],
+            [
+                252, 66, 64, 58, 146, 197, 79, 63, 196, 10, 116, 66, 72, 177, 170, 234, 252, 154,
+                82, 137, 234, 3, 117, 226, 73, 211, 32, 4, 150, 196, 133, 33,
+            ],
+            [
+                42, 33, 199, 187, 104, 139, 231, 56, 52, 166, 8, 70, 141, 53, 158, 96, 175, 246,
+                75, 186, 160, 9, 17, 203, 83, 113, 240, 208, 235, 33, 111, 41,
+            ],
+            [
+                133, 233, 196, 82, 62, 17, 13, 12, 173, 230, 192, 216, 56, 126, 197, 152, 164, 155,
+                205, 238, 73, 116, 220, 196, 21, 134, 120, 39, 171, 177, 119, 25,
+            ],
+        ];
+
+        let expected_output_0_hex_legacy =
+            "1b3251b6912d82edc78bbb0a5c88f0c6fde1781bc3e654123fa6862a4c63e617";
+        let expected_output_0_hex_kimchi =
+            "a8eb9ee0f30046308abbfa5d20af73c81bbdabc25b459785024d045228bead2f";
+
+        for param_type in [ParamType::Legacy, ParamType::Kimchi] {
+            let expected_output_bytes = match param_type {
+                ParamType::Legacy => &expected_output_bytes_legacy,
+                ParamType::Kimchi => &expected_output_bytes_kimchi,
+            };
+
+            for length in 0..6 {
+                // generate input & hash
+                let input = rand_fields(&mut rng, length);
+                let output = match param_type {
+                    ParamType::Legacy => poseidon::<constants::PlonkSpongeConstantsLegacy>(
+                        &input,
+                        pasta::fp_legacy::static_params(),
+                    ),
+                    ParamType::Kimchi => poseidon::<constants::PlonkSpongeConstantsKimchi>(
+                        &input,
+                        pasta::fp_kimchi::static_params(),
+                    ),
+                };
+
+                let mut output_bytes = vec![];
+                output
+                    .into_bigint()
+                    .serialize_uncompressed(&mut output_bytes)
+                    .expect("canonical serialization should work");
+
+                assert!(output_bytes == expected_output_bytes[length as usize]);
+            }
+
+            let expected_output_0_hex = match param_type {
+                ParamType::Legacy => expected_output_0_hex_legacy,
+                ParamType::Kimchi => expected_output_0_hex_kimchi,
+            };
+
+            let test_vectors_hex = generate(Mode::Hex, param_type);
+            assert!(test_vectors_hex.test_vectors[0].output == expected_output_0_hex);
+        }
+    }
+}
diff --git a/utils/src/field_helpers.rs b/utils/src/field_helpers.rs
index 484f2e2340..c81e87e77b 100644
--- a/utils/src/field_helpers.rs
+++ b/utils/src/field_helpers.rs
@@ -333,7 +333,7 @@ mod tests {
         let field_zero = BaseField::from(0u32);
 
         assert_eq!(
-            BigUint::from_bytes_be(&field_zero.0.to_bytes_be()),
+            BigUint::from_bytes_be(&field_zero.into_bigint().to_bytes_be()),
             BigUint::from_bytes_be(&be_zero_32bytes)
         );