diff --git a/matlab/dr1.m b/matlab/dr1.m
index 698b7c5279824cbf5b57cc5d2a81409520d4f302..0c82a77abb545db7a8eababe87ab16bc2a46c650 100644
--- a/matlab/dr1.m
+++ b/matlab/dr1.m
@@ -378,7 +378,8 @@ else  % use original Dynare solver
     % derivatives with respect to dynamic state variables
     % forward variables
     w1 =w(1:n3,n2:nd);
-    if condest(w1) > 1e9;
+    if ~isfloat(w1) && (condest(w1) > 1e9)
+        % condest() fails on a scalar under Octave
         info(1) = 5;
         info(2) = condest(w1);
         return;