Former prime minister Najib Abdul Razak has mocked DAP's Kepong MP Lim Lip Eng (photo, above) for criticising the police's swift arrest of Perak exco Paul Yong after he was accused of raping his Indonesian domestic worker.

"The cops dared to arrest a DAP elected representative accused of rape. Look, now they (the police) have been told off by a DAP leader," he said in a Facebook post.

Najib did not name Lim but shared a news article of the Kepong MP censuring police.

Lim claimed police were "hasty" in arresting Yong, stating: "Police must stop arresting people quickly, and merely based on reports lodged. Arrests can only be made after some incriminating evidence is found by the police".

Yong, 49, had denied that he raped the 23-year-old complainant. The Tronoh assemblyperson was briefly detained when he presented himself at the Jelapang police station to facilitate investigation but is now out on police bail.

The alleged victim has undergone a medical examination and is now placed at a safe house.

Najib, who is also the Pekan MP, linked Lim's response to a purported threat made by another DAP leader against the police last month.

"The authorities must be reminded about the warning from a Pahang DAP leader: 'Those who want to fight Pakatan Harapan, the time will come when they will know no peace'," he said.

Najib was referring to Jerantut DAP chief Loo Why Leong, who had sent the text message to Jerantut district police chief Mazlan Hassan following enforcement action against a DAP member.

Loo later apologised for sending the text message.

Najib said even BN did not publicly reprimand the police as no BN leader had publicly reprimanded the police for arresting suspects when it was in power.

"Not one BN leader threatened the police like how the Pahang DAP leader did.

"But DAP has extraordinary power. Rule of law? Rule of DAP," he said.