Dr Mahathir Mohamad should retire from politics with dignity, said BN strategic communications director Abdul Rahman Dahlan.

"I wish (Mahathir would stay retired) but of course it is a dream.

"We need to have culture where the former prime minister should retire with dignity," he told reporters at the Parliament lobby today.

Mahathir has actively been campaigning for Prime Minister Najib Abdul Razak to be removed from office.

The former premier is among several Umno leaders, including party deputy president Muhyiddin Yassin, who are becoming increasingly vocal against Najib.

Asked if Mahathir or Muhyiddin should be disciplined, Rahman hinted that there are grounds to do so.

"If we look at the disciplinary point of view, I believe there are some grounds to bring some people to be judged on disciplinary issues," he said.

He also said Mahathir and Muhyiddin are still subject to Umno's rules and regulations just like every other member.

"As far as I'm concerned, everybody must toe the line in terms of discipline.

"You can have different views but you have to use appropriate avenues to explain your position," he said.

Rahman said no political party can survive if its leaders and followers are not disciplined.