Taking to Facebook, he said the government should not entertain this “sudden” claim, suggesting it had never happened under his watch.

Saying it had been decades since Manila raised its Sabah claim when Barisan Nasional was in power, Najib added: “When I was the prime minister, the Philippines had never brought this issue to me.”

In assuring that Sabah is a part of Malaysia, he said: “We must not submit to and entertain other countries’ claims.”

The latest salvo from the Philippines on the issue came after its foreign affairs secretary Teodoro Locsin Jr said he will revive an office in his department dedicated to efforts to reclaim Sabah.

It was a move seen as reigniting a long-standing diplomatic row with Malaysia that had been put to bed decades ago.

Locsin, who revived the controversy by saying in July that Sabah “is not in Malaysia”, also claimed that offers of “huge” bribes had been made by Philippine presidential candidates to officials over the years to drop their claim on Sabah.