diff --git a/easybuild/easyconfigs/n/NECI/NECI-20230620-foss-2023a.eb b/easybuild/easyconfigs/n/NECI/NECI-20230620-foss-2023a.eb
index becc50b238e..09dce5c1aab 100644
--- a/easybuild/easyconfigs/n/NECI/NECI-20230620-foss-2023a.eb
+++ b/easybuild/easyconfigs/n/NECI/NECI-20230620-foss-2023a.eb
@@ -19,7 +19,11 @@ sources = [{
     },
     'filename': SOURCE_TAR_GZ,
 }]
-checksums = [None]
+patches = ['NECI-20230620_segfault.patch']
+checksums = [
+    None,
+    'f0b5f62e115a1e07d6b90bc66ee9957a5f5d686bef65beba9c2be4bd8f29f0e4',
+]
 
 builddependencies = [
     ('CMake', '3.26.3'),
diff --git a/easybuild/easyconfigs/n/NECI/NECI-20230620_segfault.patch b/easybuild/easyconfigs/n/NECI/NECI-20230620_segfault.patch
new file mode 100644
index 00000000000..0a63b605dd3
--- /dev/null
+++ b/easybuild/easyconfigs/n/NECI/NECI-20230620_segfault.patch
@@ -0,0 +1,21 @@
+Fixes SEGFAULT error in tests.
+See https://github.com/ghb24/NECI_STABLE/issues/18
+Author: Petr Král (INUITS)
+--- unit_tests/back_spawn_excit_gen/test_back_spawn_excit_gen.F90.orig	2023-06-20 10:15:17.000000000 +0200
++++ unit_tests/back_spawn_excit_gen/test_back_spawn_excit_gen.F90	2024-11-21 14:58:46.602604509 +0100
+@@ -64,6 +64,7 @@
+         nmaxy = 2
+         nmaxz = 2
+         allocate(KPointToBasisFn(-nmaxx:nmaxx, -nmaxy:nmaxy, -nmaxz:nmaxz, 2))
++        KPointToBasisFn = -1
+         tOrbECutoff = .false.
+ 
+         allocate(projedet(nel,1)); projedet(:,1) = [1,2]
+@@ -403,6 +404,7 @@
+         tOrbECutoff = .false.
+         niftot = 1
+         allocate(KPointToBasisFn(-nmaxx:nmaxx, -nmaxy:nmaxy, -nmaxz:nmaxz, 2))
++        KPointToBasisFn = -1
+ 
+         t_back_spawn_flex = .true.
+         occ_virt_level = 0