KUALA LUMPUR - Malaysia's famed jailed politician Anwar Ibrahim, once the country's opposition leader and deputy prime minister, is slated to be released from prison next Tuesday (May 15).

Two top officials from his Parti Keadilan Rakyat (PKR) confirmed to The Straits Times that Anwar will be released once the pardon is issued on Tuesday.

"Pardon (is) based on a miscarriage of justice," said Anwar's daughter Nurul Izzah Anwar, who is also Permatang Pauh MP in a WhatsApp text to The Straits Times.

Anwar, 70, has been in prison since 2015 for a second sodomy charge which leaders of the Pakatan Harapan coalition had tagged as politically motivated.

He was supposed to be released from prison on June 8, according to the Prisons Department in a statement this January.

During the meeting between King Muhammad V and the leaders of Pakatan Harapan on Thursday, the matter of Anwar's pardon and release was raised.

Newly minted Prime Minister Tun Mahathir Mohamad told a press conference on Saturday that there is a process to be followed but that it would be "expedited as soon as possible".

PKR vice-president Shamsul Iskandar said the paperwork will be dealt with on Monday, with the pardon to be issued on Tuesday followed by Anwar's immediate release.

Anwar has been in a rehabilitation centre since March after an adverse reaction to a steroid injection on his shoulder, post surgery.

A video of Anwar watching from his hospital room the swearing-in ceremony of Dr Mahathir as prime minister on Thursday went viral on social media.

Pakatan Harapan has named Anwar as the prime minister-in-waiting, with Dr Mahathir having promised to vacate the seat once Anwar is pardoned, released and elected as a lawmaker.