AYER ITAM: Malaysiainfo-icon's scandal-plagued prime minister and his rival, 92-year-old former authoritarian leader Mahathir Mohamad, made final pitches for votes on Tuesday on the eve of one of the tightest electionsinfo-icon in the country's historyinfo-icon.

Prime Minister Najib Razak faces a tough fight at Wednesday's polls to retain power at the head of the coalition that has ruled Malaysia for six decades, in the face of a challenge from Mahathir.

The veteran ex-leader, who led Malaysia with an iron fist for 22 years, came out of retirement to take on his former protege Najib due to an explosive corruptioninfo-icon scandal surrounding sovereign wealth fund 1MDB.

Mahathir has thrown in his lot with an opposition alliance packed with parties he crushed while in power, electrifying an election race that had long looked like an easy win for the ruling Barisan Nasional coalition.

However most analysts still expect the government to edge another victory, as they have tight control of Malaysia's weakened institutions, while critics accuse them of wide-spread manipulation of the electoral system.

In a speech on the northwest island of Langkawi, which was broadcast live to rallies across the country and on Facebookinfo-icon, Mahathir urged voters to swing behind his opposition alliance, Pact of Hope.

"We need to defeat Najib and Barisan Nasional because our country has been destroyed," he said. "We can only regain our dignity by changing the government."

Najib has been accused of involvement in the scandal surrounding 1MDB, in which billions of dollars were allegedly looted from the fund in a campaign of fraud and money-laundering. Najib, who set up the fund, and 1MDB deny any wrongdoing.

Mahathir spoke in front of a large picture of himself with jailed opposition icon -- and his former nemesis -- Anwar Ibrahim, showing both men smiling.

The pair fell out dramatically in the 1990s -- with Anwar imprisoned during Mahathir's rule -- but have joined forces again to take on the government, in one of the most dramatic twists of a gripping election season.

In an address on state TVinfo-icon that aired at the same time as his rival's speech, Najib announced a series of measures that will be implemented if the government wins.

These included people aged 26 and below being exempted from income tax, and two additional public holidays. "Barisan Nasional is a party that looks to the future," he said.

"We are not a party of the past, we don't play with leaders who have already retired." The ruling coalition, which has governed Malaysia since independence in 1957, has seen its popularity slide in recent years due to graft scandals, divisive racial politics in the multi-ethnic country and anger at rising living costs.

But it will be tough for the opposition to beat BN, with critics accusing the coalition of gerrymandering and engaging in electoral fraud. The coalition insists the elections are free and fair.