Posters advertising the New Zealand Comedy Festival have been withdrawn after sponsor Cadbury received complaints that its dig at dyslexics wasn't funny.

Posters for the festival in Wellington and Auckland reading: "10 out of 9 dyslexics prefer Crunchie" had drawn the ire of the Dyslexic Foundation, The Dominion Post reported.

"You certainly wouldn't make comments like that about other groups who have a disability," foundation spokesman Guy Pope-Mayell said.

The posters were insensitive to people living with dyslexia, and misrepresented the condition as not all dyslexics transposed numbers and letters.

Cadbury had immediately withdrawn the posters from Auckland buses and bus stops, and apologised for any offence, company spokesman Daniel Ellis said.

- NZPA