diff --git a/flepimop/gempyor_pkg/tests/seir/test_seir.py b/flepimop/gempyor_pkg/tests/seir/test_seir.py
index 16bbd390c..9e4aa5cc2 100644
--- a/flepimop/gempyor_pkg/tests/seir/test_seir.py
+++ b/flepimop/gempyor_pkg/tests/seir/test_seir.py
@@ -3,6 +3,8 @@
 import pytest
 import warnings
 import shutil
+from random import randint
+import pandas as pd
 
 import pathlib
 import pyarrow as pa
@@ -15,6 +17,43 @@
 DATA_DIR = os.path.dirname(__file__) + "/data"
 os.chdir(os.path.dirname(__file__))
 
+def test_neg_params():
+    modinf = model_info.ModelInfo(
+        config=config,
+        nslots=1,
+        seir_modifiers_scenario="None",
+        write_csv=False,
+    )
+        
+    modinf = model_info.ModelInfo()
+    parameter_names = modinf.parameters.pnames
+    dates = modinf.dates
+    subpop_names = modinf.subpop_pop
+
+    # Test case 1: no negative params
+    test_array1 = np.zeros((len(parameter_names)-1, len(dates)-1, len(subpop_names)-1))
+    
+    # Test case 2: randomized negative params
+    test_array2 = np.zeros((len(parameter_names)-1,len(dates)-1,len(subpop_names)-1))
+    for _ in range(5):
+        test_array2[randint(0,len(parameter_names)-1)][randint(0,len(dates)-1)][randint(0,len(subpop_names)-1)] = -1
+
+    # Test case 3: set negative params with intentional redundancy
+    test_array3 = np.zeros((len(parameter_names),len(dates),len(subpop_names)))
+    randint_first_dim = randint(0,len(parameter_names)-1)
+    randint_second_dim = randint(0,len(dates)-2)
+    randint_third_dim = randint(0,len(subpop_names)-1)
+    test_array3[0][0][0] = -1
+    test_array3[randint(0,len(parameter_names)),randint(0,len(dates)):,randint(0,len(subpop_names))] = -1
+    test_array3[randint_first_dim][randint_second_dim][randint_third_dim] = -1
+    test_array3[randint_first_dim][randint_second_dim+1][randint_third_dim] = -1
+
+    seir.neg_params(test_array1, parameter_names, dates, subpop_names) # NoError
+
+    with pytest.raises(ValueError):
+        assert seir.neg_params(test_array2, parameter_names, dates, subpop_names) # ValueError
+        assert seir.neg_params(test_array3, parameter_names, dates, subpop_names) # ValueError
+
 
 def test_check_values():
     os.chdir(os.path.dirname(__file__))