Anwar, who was the deputy prime minister during Mahathir's premiership in the 1990s, is now in a hospital in Cheras, waiting for the Pardons Board meeting, scheduled for Wednesday morning, said Bernama.
Saifuddin Nasution, a party leader in the ruling Pakatan Harapan coalition, told reporters that Anwar is also expected to attend a gathering with his supporters after his release.
Mahathir, 92, who put Anwar in jail in 1998, promised to help release his former protege during the campaign.
He also pledged to serve the premiership for around two years before handing it over to Anwar. But Anwar needs to win a by-election to become a parliamentary member first.
Anwar was previously scheduled to be released on June 8. He was serving a five-year jail term on sodomy charges.
