Face Dr Mahathir Mohamad in the arena like a gladiator. This is Penang Chief Minister Lim Guan Eng's advice to Prime Minister Najib Abdul Razak.

Lim called on Najib to take on Mahathir in a debate instead of penning responses in his blog.

"Have a debate. Instead of writing in his blog and FAQ in a controlled and laboratory-like environment. Let the people decide.

"Go into a real life arena. Battle it out, man-to-man, with Mahathir," Lim told a press conference in Kuala Lumpur.

As for Mahathir calling on Lim to resign as well, the chief minister did not wish to be drawn into a mud-slinging match with the former premier.

"I don't want to be drawn into the Najib- Mahathir battle. Let them fight. See who comes out with better arguments.

"While I disagree with Mahathir's attack against me, I feel that Najib should respond to Mahathir’s challenge to a debate," he added.

Yesterday, Mahathir said Lim should resign because the change of government in Penang had brought about an "antagonistic" situation.

"Look, for 60 years we have had stability in this country and this country grew very well. But now we have different governments operating in different states.

"You have this antagonism thing and you fall back on racist sentiments and things like that. Thus of course, you not doing the country any good,” Mahathir had said.