Former prime minister Dr Mahathir Mohamad today said his tussle with Prime Minister Najib Abdul Razak was a choice between a crisis or allowing billions to be stolen by thieves.

"A crisis may be the result, but should we allow thieves to steal billions of ringgit in order to avoid a crisis?" Mahathir said in his blog posting today.

This is after Najib accused Mahathir of starting a "big mess" by attacking him.

Mahathir wrote: "I will admit that I am behind the 'crisis'. I am behind it because there is a climate of fear in this country.

"Lots of people know about the loss of billions of ringgit by 1MDB. These people are in a position to know because they have seen evidence of this loss.

"But they are afraid because of actions which the government can take against them. They may lose their jobs, or contracts or expectations of titles."

'Najib wants a blind eye turned on 1MDB'

He said these people had then approached him to "do something" which he finally did after holding back for a long time.

Mahathir added that Najib blaming him for the crisis is akin to asking the people to turn a blind eye on 1MDB.

"Najib is saying let us accept the disappearance of the billions of ringgit and behave as if nothing wrong has been done.

"From the interest and concern shown by the people over the losses suffered by 1MDB, the matter cannot just be ignored.

"The people responsible must be investigated and if found guilty, they must be punished," he said.

While admitting to be "behind" the crisis, Mahathir said it was ultimately started by Najib himself.

"Is there a crisis? There is. It is caused by the prime minister creating 1MDB borrowing huge sums of money and losing billions of ringgit.

"The crisis can be ended immediately if the prime minister resigns and allows a full investigation to be made on the RM42 billion borrowed by 1MDB," he said.