Mahathir Mohamad, 92, said Thursday he expects to be sworn in as prime minister soon, quelling concerns around the succession after his stunning win over the scandal-plagued coalition that has ruled for six decades.
In a huge political upset, Mahathir's opposition alliance ended the hold on power of the Barisan Nasional (BN) coalition, which has governed Malaysia uninterrupted since its birth as an independent country in 1957.
It capped a dramatic political comeback for Mahathir, who previously ruled the country with an iron fist for 22 years and came out of retirement to take on Prime Minister Najib Razak after the leader became embroiled in a massive corruption scandal.
Mahathir was expected to be sworn in at 5:00 pm (0900 GMT), and will be the world's oldest leader.
In a volte-face, Mahathir had thrown in his lot with an alliance of opposition parties he crushed while in power, which included jailed opposition icon Anwar Ibrahim -- his former nemesis.
Mahathir has pledged to get Anwar, who is due out of jail in June, a royal pardon and eventually pass the premiership to a man who is one of the country's most charismatic and popular politicians.
However concerns mounted about the transfer of power Thursday morning after Mahathir was not inaugurated by the king, as had been widely expected.
He said there had been some delays due to confusion over certain parts of the constitution but this had now been cleared up, and called for his inauguration to take place by 5:00 pm.
"We expect today for me to be sworn in as prime minister," he told a press conference.
"There is an urgency here. Currently there is no government in Malaysia."
His speech came after Najib, in his first public comments since his shock loss, said he accepted the people's will -- but did not give a clear concession, and said that it was up to the king to decide on the prime minister as no single party had won a clear majority.
"I accept the verdict of the people and BN is committed to the principles of democracy," said Najib, looking shattered.
Analysts warned he could be trying to buy time to win defections from other parties over to BN, in what would be a desperate bid to cling to power despite a landslide defeat.
To claim a simple majority in parliament, a party or coalition would require 112 seats.
The opposition alliance, Pact of Hope, along with a small ally on Borneo island, won 121. BN won just 79 -- down from 133 previously.
However the official Election Commission listed the scores for the alliance's separate component parties when they released the results, not the overall score for the alliance as a whole.
The opposition's shock victory triggered euphoria and a sense of relief that a leader who was accused of massive graft and fanning racial tensions was finally on his way out.
"We have been waiting for so long for this to happen," Larson Michael, 35, a voter from just outside Kuala Lumpur, told AFP.
"(Mahathir) has come back to help us regain the country. Now we want to see if he will fulfil... his promises."
The opposition faced an uphill battle at the election due to what critics said were no-holds-barred attempts by Najib to hang on to power.
His government was accused of gerrymandering while activists said he hurled cash and gifts at voters and there was a litany of problems with the electoral roll, including dead people appearing on the list.
Najib's defeat could be just the start of his problems -- Mahathir has vowed to bring him to justice over allegations that billions of dollars were looted from sovereign wealth fund 1MDB, which the scandal-hit leader set up and oversaw.
In Mahathir, the opposition found the perfect person to take on Najib. He is a staunch Malay nationalist who could appeal to the country's biggest ethnic group, and whose years in power were remembered as a prosperous period in the country's history.
The initial euphoria at the opposition victory will likely give way to some apprehension.
Mahathir was also accused of being an authoritarian leader, and political opponents were thrown in jail during his time in office.