KUALA LUMPUR (April 19): Former prime minister Tun Dr Mahathir Mohamad said he regrets not having put in place stronger checks and balances on power when he was prime minister.

"I did not know it at the time, of course, but I regret very much that I was not able to foresee the kind of damage that can be done by a prime minister under the existing law," he said in an interview with The Associated Press yesterday.

Mahathir was prime minister of Malaysia from 1981 till his retirement in 2003. He is currently chairman of the opposition's Parti Pribumi Bersatu Malaysia.

On the upcoming elections, Mahathir said if incumbent prime minister Datuk Seri Najib Razak were to retain power, the country would be bankrupted due to ballooning national debts that the government cannot pay. "This country will be totally destroyed," he said.

He said even though rural Malays underestimate the scale of Najib's involvement in the 1MDB scandal, they have been hard hit by the rising cost of living due to the introduction of the 6% goods and services tax in 2015 to raise government revenue.

He added that huge rallies indicate some of the ruling coalition's traditional Malay supporters are now favouring the opposition and a change of government is possible in next month's elections.

The opposition wouldn't need every government supporter to change their mind. "We need maybe 30% of them to turn around — that would be sufficient for us to win," he said.

"Now wherever we go, we have a huge number of people coming to us and most of them are Malays," Mahathir said in reference to the crowd at opposition rallies.

"They will come out and they will listen to the talks until the very end. They don't move, they don't go away. It shows their interest.

"I think there is a wave — whether you call it a tsunami or not, I don't know — but there certainly is a change of heart among the rural Malays," he said.

However, Mahathir predicted only a 50-50 chance of victory for the opposition "because of the government's tendency to cheat, to threaten people, to use money, to even block the election process".

In the event of an opposition victory, Mahathir warned that there could be instability if the win is small.

"With Najib, we can never be very sure that he wouldn't resort to illegal means to retain his position. So if the majority we obtain is small, he might create a problem," he said.

Mahathir said the opposition will reopen investigations into 1MDB if it wins the election, he said, but denied they would be targeted at Najib.

"If it reaches the court, the court will decide, we are not going to decide," Mahathir said. "It is not a question of revenge. We are not going to take revenge on him, but the law must be respected."