diff --git a/numba/cpython/hashing.py b/numba/cpython/hashing.py
index 5119e8a32..01ec6da94 100644
--- a/numba/cpython/hashing.py
+++ b/numba/cpython/hashing.py
@@ -6,6 +6,7 @@ import math
 import numpy as np
 import sys
 import ctypes
+import warnings
 from collections import namedtuple
 
 import llvmlite.binding as ll
@@ -460,7 +461,22 @@ _hashsecret = _build_hashsecret()
 # ------------------------------------------------------------------------------
 
 
-if _Py_hashfunc_name == 'siphash24':
+if _Py_hashfunc_name in ('siphash24', 'fnv'):
+
+    # Check for use of the FNV hashing alg, warn users that it's not implemented
+    # and functionality relying of properties derived from hashing will be fine
+    # but hash values themselves are likely to be different.
+    if _Py_hashfunc_name == 'fnv':
+        msg = ("FNV hashing is not implemented in Numba. See PEP 456 "
+               "https://www.python.org/dev/peps/pep-0456/ "
+               "for rationale over not using FNV. Numba will continue to work, "
+               "but hashes for built in types will be computed using "
+               "siphash24. This will permit e.g. dictionaries to continue to "
+               "behave as expected, however anything relying on the value of "
+               "the hash opposed to hash as a derived property is likely to "
+               "not work as expected.")
+        warnings.warn(msg)
+
     # This is a translation of CPython's siphash24 function:
     # https://github.com/python/cpython/blob/d1dd6be613381b996b9071443ef081de8e5f3aff/Python/pyhash.c#L287-L413    # noqa: E501
 
@@ -608,10 +624,6 @@ if _Py_hashfunc_name == 'siphash24':
         v0, v1, v2, v3 = _DOUBLE_ROUND(v0, v1, v2, v3)
         t = (v0 ^ v1) ^ (v2 ^ v3)
         return t
-
-elif _Py_hashfunc_name == 'fnv':
-    # TODO: Should this instead warn and switch to siphash24?
-    raise NotImplementedError("FNV hashing is not implemented")
 else:
     msg = "Unsupported hashing algorithm in use %s" % _Py_hashfunc_name
     raise ValueError(msg)

Build failed: fatal error: omp.h: No such file or directory
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I have added python3, python-llvmlite, python-numpy dependencies for numba-0.48.0 version. Build is failing due to missing omp.h please check this [numba_build_log](https://paste.ubuntu.com/p/9V7HKnvtfr/) 
diff --git a/numba/tests/test_hashing.py b/numba/tests/test_hashing.py
index b4760dc0d..d139a229e 100644
--- a/numba/tests/test_hashing.py
+++ b/numba/tests/test_hashing.py
@@ -6,7 +6,9 @@ Test hashing of various supported types.
 import unittest
 
 import sys
+import subprocess
 from collections import defaultdict
+from textwrap import dedent
 
 import numpy as np
 
@@ -23,6 +25,47 @@ def hash_usecase(x):
     return hash(x)
 
 
+class TestHashingSetup(TestCase):
+
+    def test_warn_on_fnv(self):
+        # FNV hash alg variant is not supported, check Numba warns
+        work = """
+        import sys
+        import warnings
+        from collections import namedtuple
+
+        # hash_info is a StructSequence, mock as a named tuple
+        fields = ["width", "modulus", "inf", "nan", "imag", "algorithm",
+                  "hash_bits", "seed_bits", "cutoff"]
+
+        hinfo = sys.hash_info
+        FAKE_HASHINFO = namedtuple('FAKE_HASHINFO', fields)
+
+        fd = dict()
+        for f in fields:
+            fd[f] = getattr(hinfo, f)
+
+        fd['algorithm'] = 'fnv'
+
+        fake_hashinfo = FAKE_HASHINFO(**fd)
+
+        # replace the hashinfo with the fnv version
+        sys.hash_info = fake_hashinfo
+        with warnings.catch_warnings(record=True) as warns:
+            # Cause all warnings to always be triggered.
+            warnings.simplefilter("always")
+            import numba
+            assert len(warns) > 0
+            expect = "FNV hashing is not implemented in Numba. See PEP 456"
+            for w in warns:
+                if expect in str(w.message):
+                    break
+            else:
+                raise RuntimeError("Expected warning not found")
+        """
+        subprocess.check_call([sys.executable, '-c', dedent(work)])
+
+
 class BaseTest(TestCase):
 
     def setUp(self):

pip install -e .[dev]
parse_log_pytest
requirements.txt
pytest pytest-cov
apt-get update apt-get install -y gcc g++
3.7
requirements.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
certifi @ file:///croot/certifi_1671487769961/work/certifi
coverage==7.2.7
exceptiongroup==1.2.2
importlib-metadata==6.7.0
iniconfig==2.0.0
llvmlite==0.31.0
-e git+https://github.com/numba/numba.git@a4c4a8dceb0801672d6fda9199c36047dba16f0b#egg=numba
numpy==1.21.6
packaging==24.0
pluggy==1.2.0
pytest==7.4.4
pytest-cov==4.1.0
tomli==2.0.1
typing_extensions==4.7.1
zipp==3.15.0

name: numba
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2022.12.7=py37h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - pip=22.3.1=py37h06a4308_0
  - python=3.7.16=h7a1cb2a_0
  - readline=8.2=h5eee18b_0
  - setuptools=65.6.3=py37h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - wheel=0.38.4=py37h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - argparse==1.4.0
      - coverage==7.2.7
      - exceptiongroup==1.2.2
      - importlib-metadata==6.7.0
      - iniconfig==2.0.0
      - llvmlite==0.31.0
      - numpy==1.21.6
      - packaging==24.0
      - pluggy==1.2.0
      - pytest==7.4.4
      - pytest-cov==4.1.0
      - tomli==2.0.1
      - typing-extensions==4.7.1
      - zipp==3.15.0
prefix: /opt/conda/envs/numba

numba/tests/test_hashing.py::TestHashingSetup::test_warn_on_fnv
numba/tests/test_hashing.py::TestNumberHashing::test_bool numba/tests/test_hashing.py::TestNumberHashing::test_complex numba/tests/test_hashing.py::TestNumberHashing::test_floats numba/tests/test_hashing.py::TestNumberHashing::test_ints numba/tests/test_hashing.py::TestTupleHashing::test_heterogeneous_tuples numba/tests/test_hashing.py::TestTupleHashing::test_homogeneous_tuples numba/tests/test_hashing.py::TestUnicodeHashing::test_basic_unicode numba/tests/test_hashing.py::TestUnicodeHashing::test_hash_on_str_creation numba/tests/test_hashing.py::TestUnicodeHashing::test_hash_passthrough numba/tests/test_hashing.py::TestUnicodeHashing::test_hash_passthrough_call
numba/cpython/hashing.py
numba/cpython/hashing.py