Mahathir Mohamad is urging voters to support Anwar Ibrahim's return to active politics in Sunday's byelection.
The newly pardoned reformer says the government's foreign policy has been tainted.
Jailed on trumped-up sodomy charges,Anwar was released after a royal pardon,starting an expected transition to the prime ministership.
The hopes for non-racial politics and economic reform represented by Anwar Ibrahim contrast with the Malay-first policies of his coalition partner.
Poised for release from prison,Malaysia's Anwar Ibrahim breaks his silence to say Malaysia is on the verge of a new"golden era".
Twice jailed opposition leader Anwar to get Malay king pardon
Malaysia's 14th general election looks set to go to the wire,but Prime Minister Najib Razak is favourite to win over his former mentor,Mahathir Mohamad.
Malaysia's opposition desperately wants this to be a"change"election. It probably won't be. But hope is burning bright.
Deputy Malaysian opposition leader Wan Azizah predicts the May 9 poll might not deliver a firm result. Analysts are not so sure.
The 92-year-old former Malaysian PM is on the campaign trail after joining forces with a bitter rival to try to blast prime minister Najib Razak out of office.