Former premier Najib Abdul Razak has said he would be willing to take a bet that Pakatan Harapan's purported election promise to bring down fuel prices was nothing more than a fairy tale to win hearts of the people.

In an interview with Sinar Harian, Najib claimed the Harapan government has lied to the people about its promise to bring down fuel prices.

"I dare to take on a bet with anyone. I dare to bet that the (promise of) fuel prices decrease to RM1.50 per litre is nothing more than a fairy tale.

"But unfortunately our youths, the first time voters, they can't see beyond that (the promise)," Najib was quoted as saying.

Najib further said he believes that Harapan's promise will never happen, even "if cats grew horns."

"I know that fuel prices cannot go down to RM1.50 (per litre), so don't lie.

"I know because I was finance minister at the time. I knew the implications if the fuel price was brought down to RM1.50," the Pekan MP was quoted as saying.

Najib did not elaborate on the source of his claim about Harapan's promise.

The previous BN administration under Najib introduced the weekly float mechanism for fuel prices in March last year after deciding to abolish fuel subsidies.

The weekly fuel price was calculated based on regional benchmark prices provided by Means of Platts Singapore (Mops).

Harapan's GE14 manifesto had promised to "stabilise the price of fuel and reintroduce targeted subsidies".

However, the manifesto does not mention bringing the price down to RM1.50.

Slightly a week after the May 9 general elections, Prime Minister Dr Mahathir Mohamad announced that the government would end price fluctuations at the pump and reintroduce subsidies if it found a need to do so.

Pump prices have remained constant and have not risen since the general election, observed popular motoring website Paultan.org.