Former prime minister Najib Abdul Razak has described as "stupid" Bersatu information chief Wan Saiful Wan Jan's challenge for Umno to parade their central leaders during the upcoming Johor polls.

Wan Saiful had suggested that leaders such as Najib and Umno president Ahmad Zahid Hamidi are tainted due to their graft charges and challenged if Umno dared to use them as symbols during the state polls.