Prime Minister Najib Abdul Razak today took to Indonesian media to explain his fallout with former premier and mentor Dr Mahathir Mohamad.

Speaking to MetroTV in an interview, Najib related that Mahathir was "obsessed about control" and was trying to call the shots even though he was no longer the prime minister.

"I only had two choices as prime minister. First, that I become a prime minister who refers to him and get his 'advice'.

"I say advice but it's probably instructions to do what he wants in terms of the administration of the country.

"Or, I become a prime minister who believes in my own leadership, judgement and the mandate given to me by the country and my party, and do what I think is best for the country.

Asked by the interviewer which choice did he make, Najib said it is the latter.

"I need to be a prime minister who is responsible to the rakyat (and) do what I think is best for the country.

"But I know the effect of this is that Mahathir will not be happy with me because history has shown that he has dismissed and got rid of many prime ministers before this," he said.

This was Najib's first international interview after the US Department of Justice (DOJ) claimed more than US$3.5 billion was siphoned from Malaysian state-fund 1MDB and was confiscating US$1 billion in assets acquired through the stolen money.

Najib was asked about the DOJ action in the interview but claimed it did not involve him.

He also claimed the 1MDB scandal is merely a "business" issue and the opposition was politicising it to unseat him.