After almost a year of constant attacks against the leadership of Prime Minister Najib Abdul Razak, Dr Mahathir Mohamad reiterated today that there would be no let-up by him in efforts to unseat the current PM.

"Well, I always believe that when you fail, you get up and try again and again. It's whether that what we have been doing is worthwhile or not," the nation's longest-serving premier of 22 years said.

He was speaking to reporters after launching the 'My New Proton' initiative in Shah Alam today.

To a question that his efforts from April last year have failed to kick out Najib from office, Mahathir said that the nation's laws were not being implemented properly.

“The existing law is not being implemented properly. New laws are then formulated for another purpose and people get arrested and tried.

“I know that during my time we had the ISA but I did not use it to harass people who criticised me. Only when they did something to the country.”

Mahathir also noted that questioning the administration was part of a democracy.

“If you criticise the government now, you are going to be detained, questioned and put on trial. If you can't criticise, then where is the democracy?

“The law is applied differently depending who you are. So somebody has to say something. I have to say it because I want the country to have a good reputation.”

Country is 'shameful'

Mahathir also said that he had never advocated violence is pursuing a change in leadership.

“Today the country's reputation is rotten. People ask me what has happened to your country? It's shameful. All because of one man's leadership.

“If we go wrong, we need to change in a peaceful way. I do not advocate violence.

But when I speak up, then I am harassed with arrest ,” he said, referring to calls by certain Umno leaders that his blog posts were seditious.

Asked what his next move will be, Mahathir said that the problem was still Najib's leadership.

“I still emphasise the need for Najib to step down. Everything goes back to him,” he said.