Dr Mahathir Mohamad will not work with the opposition to force Prime Minister Najib Razak to resign.

"No, I'm not working with anyone to bring down Najib, certainly not the opposition.

"The problem is within Umno itself," the former premier told reporters at the Putra World Trade Centre on Sunday.

On Saturday, DAP adviser Lim Kit Siang had said that is ready to put aside part problems and work together with Dr Mahathir if that is what it takes to save the country.

"For this formidable task, we must be prepared to put our differences in the past to one side and concentrate all our energies on one common agenda, to save Malaysia from all centrifugal forces to tear the country asunder.

"On this agenda, I am prepared even to work with Tun Mahathir to 'Save Malaysia'," Lim had said in a transcript of a speech to Malaysian students in Egypt published on his blog.

Lim was referring to the Save Malaysia coalition, which he had first spoken about last month.