Malaysia's Prime Minister Abdullah Ahmad Badawi says he will not resign despite a big setback for his governing coalition in Saturday's election.
Chinese and Indian ethnic minority voters deserted the ruling coalition
The National Front lost its two-thirds majority in parliament - its worst result since independence in 1957.
But it did get 139 MPs in the 222-seat body, giving it a simple majority.
Many voters from ethnic minorities - Indians and Chinese - who make up more than a third of the population, failed to turn out for the coalition.
Concern about a government failure to tackle renewed ethnic tension is one of the main reasons for the upset, says the BBC's Robin Brant in Kuala Lumpur.
Mahathir Mohamad says the PM should step down
Many of the coalition's Malay supporters abandoned it too.
Among those calling for Mr Abdullah to quit is his predecessor, Mahathir Mohamad, who accused him of destroying the United Malays Organisation (UMNO), the largest party in the National Front alliance.
Mr Mahathir, who chose Mr Abdullah as his successor more than five years ago, said he had made the wrong choice.
"I think he should accept responsibility for this. He should accept 100% responsibility," he said.
Mr Abdullah responded to calls for his resignation by telling reporters: "There is no pressure at this time."
He also urged calm, amid fears there may be violence in the wake of the result.
Mr Abdullah plans to meet the monarch on Monday to seek the oath of office, his spokesman said.
The opposition now has control of an unprecedented number of seats in parliament - more than 80. Before the election, it held 19. More than 30 went to opposition figure Anwar Ibrahim and his Justice Party.
He hailed the result as a message that it was time for change in Malaysia.
"This is a defining moment, unprecedented in our nation's history. Today a new chapter has opened."
Sunday's edition of the Star newspaper in Malaysia dubbed the result a "political tsunami".
The election also saw more state legislatures come under opposition control. Before the poll only Kelantan had an opposition administration.
The Election Commission confirmed opposition wins in Kelantan as well as Selangor, Perak, Kedah and Penang.