Former prime minister Dr Mahathir Mohamad has to form a new party because the opposition considers him a liability, said an Umno minister.

"The fact he has to form a new party shows the other (opposition) parties won't accept him because he's a liability," Tourism and Culture Minister Nazri Abdul Aziz said.

One of Mahathir's lieutenants, Khairuddin Abu Hassan yesterday revealed that there are plans to form a new party that might be spearheaded by the former premier.

Khairuddin said this would be discussed at a meeting with opposition leaders in Putrajaya tomorrow.

Nazri welcomed the move, saying it is a legitimate way to oppose the government in a democracy.

"And Khairuddin said he would be inviting all those who are unhappy with Umno, so there's a new home for them," he added.

Speaking at a press conference in Kuala Lumpur today, Nazri also joked about the party's possible leadership line-up.

"Mahathir will be the president, former deputy prime minister Muhyiddin Yassin will be the deputy.

"(Mahathir's son) Mukhriz is the youth chief, (former Umno minister) Rafidah Aziz the Wanita chief, and Khairuddin will be the tea boy," he said.

The Umno supreme council member believes the new party would probably do worse than former Umno splinter party Semangat 46.

He said this was based on BN's thumping victories in last month's Sungai Besar and Kuala Kangsar by-elections.

Mahathir had billed the twin polls as a referendum on Najib's leadership.

The former premier has been on a warpath to oust Najib, but has thus far failed to make an impact.