KUALA LUMPUR, Malaysia — Malaysia’s political future was cast into doubt on Thursday, after a historic victory for an opposition bloc led by the country’s 92-year-old former prime minister, Mahathir Mohamad, instead was delayed when the country’s ceremonial monarch would not immediately swear him in.
The reason for the delay was uncertain. Analysts said there were standing questions over whether Mr. Mahathir’s coalition was properly registered, but it was unclear whether that was the holdup. Opposition figures worried that the defeated prime minister, Najib Razak, had influenced the king in order to buy time to work a deal.
The official result of the parliamentary elections on Wednesday was a clear majority for Mr. Mahathir’s coalition. It appeared Malaysia would see its first transfer of power to the opposition since its independence from Britain in 1957.
But the entrenched government of Mr. Najib had appeared for much of the day to be holding out hope that Malaysia’s monarch might refrain from asking Mr. Mahathir to form a government.
Mr. Najib, during his national address on Thursday morning, was grim. He took no questions from the press, and even as he appeared to concede, saying he would “accept the verdict of the people,” he also suggested that the final result might be in doubt.
He said it would be up to the king to decide who should be sworn in as prime minister.
“This was an election which saw a tough fight,” he said. “But this is a manifestation of the democracy we practice.”
Mr. Mahathir, in a national address on Thursday morning, declared that it was time for Malaysia to honor “the rule of law,” and said that the king should put him in office by 5 p.m.
“Any delay will mean that we have no government, and when you say you have no government, you have no law, you have no constitution,” Mr. Mahathir said. “You don’t have all the institutions which are created to give form to the government of this country.”
But by 6:30 p.m., no announcement from the palace was in sight. Some news organizations said the palace had decided not to conduct any ceremony on Thursday, but that could not be confirmed.
The official election result was a clear rejection of Mr. Najib’s coalition, led by his party the United Malays National Organization, which after six decades in power had come to represent corruption and the arbitrary use of authority to maintain power.
As the leader of an improbably broad opposition coalition, united primarily by outrage over the towering list of corruption accusations against Mr. Najib, Mr. Mahathir has promised to rebuild government institutions and fight corruption. He has also vowed to lead a more inclusive government beyond the country’s ethnic Malay Muslim majority that Mr. Najib catered to.
Supporters hope that Mr. Mahathir has shed his old autocratic ways and will embrace democracy and human rights, and fulfill his vow to seek a full pardon for the imprisoned former opposition leader, Anwar Ibrahim, and cede power to him if that happens.
Mr. Mahathir has also said he would clear the way for criminal prosecution of Mr. Najib, who is accused of taking $731 million in government funds.
More broadly, Mr. Najib has been embroiled in a scandal involving billions of dollars that disappeared from a government investment fund that he once headed, 1Malaysia Development Berhad. The United States Justice Department concluded that $3.5 billion from the Malaysian fund was laundered through financial institutions in the United States and spent on items like expensive real estate, jewelry, paintings and the production of movies.
Cynthia Gabriel, executive director of the Center to Combat Corruption and Cronyism in Kuala Lumpur, said she expected a new government would open a proper investigation of Mr. Najib and the missing funds, and to begin cooperating with the U.S. Justice Department and other foreign investigations.
“There is a lot of work to be done to undo the years of unbridled power,” she said.
Malaysia is a country of about 31 million that encompasses much of the Malay Peninsula and most of northern Borneo. Relatively stable, and prosperous, it sits alongside an important trade route. Its institutions and infrastructure are more developed than many of its neighbors in Southeast Asia.
Sharon Tan contributed reporting.