Portugal's third general election in three years has failed to deliver the result that could break the worst spell of political instability for decades in the European Union country of 10.6 million people.

Sunday's vote delivered another minority government for the centre-right Democratic Alliance, which will be at the mercy of opposition parties. The significant rise in support for the hard-right populist party Chega (which means "Enough") adds more uncertainty.

"We've done what no other party has ever achieved in Portugal. We can safely declare in front of all the country today that bipartisanship in Portugal is over," Chega Leader Andre Ventura told jubilant supporters in Lisbon.

"Nothing will be as it was," he said, highlighting the fact that the continued rise of Chega, which he founded just six years ago, proved most opinion polls wrong.

In Portugal, local media reported that anti-immigration rhetoric helped fuel Chega's historic rise. And experts have noted it's part of a broader trend that echoes the U.S. and the European Union.

"There has been a process of gradual shift to the right throughout the world," Bruno Madeira, historian and professor at the University of Minho, told Portuguese newspaper Jornal de Notícias on Monday.

Why was there an early election?

The Democratic Alliance, led by the Social Democratic Party, lost a vote of confidence in parliament in March as opposition lawmakers teamed up against it. That triggered an election, which had been due in 2028.

The confidence vote was sparked by a political storm around potential conflicts of interest in the business dealings of Prime Minister Luís Montenegro's family law firm. Montenegro, who is poised to become prime minister again, has denied any wrongdoing.

What was the outcome of Sunday's ballot?

The Democratic Alliance captured at least 89 seats in the 230-seat National Assembly. Chega collected the same number of seats as the centre-left Socialists — 58 — and could yet claim second place when four remaining seats decided by voters abroad are attributed in coming days.

Chega won a record 1.34 million votes, or 22.6 per cent. In the previous vote, it won two out of four seats reserved for overseas voters.

Chega competed in its first election just six years ago, when it won one seat, and has fed off disaffection with the more moderate traditional parties. Its success shook up the traditional balance of power, in a trend already witnessed elsewhere in Europe with parties such as France's National Rally, the Brothers of Italy and Alternative for Germany, which are all now in the political mainstream.

For the past 50 years, the Social Democrats and the centre-left Socialist Party have alternated in power in Portugal. The Socialists, meanwhile, are without a leader, after Pedro Nuno Santos said he was standing down following the party's worst result since 1987.

Smaller parties got the other seats.

What are the issues?

Corruption scandals have dogged Portuguese politics in recent years, helping fuel Chega's rise.

Chega owes much of its success to its demands for a tighter immigration policy, which have resonated with voters.

Portugal has witnessed a steep rise in immigration. In 2018, less than 500,000 immigrants in Portugal had legal residency, according to government statistics. By early this year, there were more than 1.5 million, many of them Brazilians and Asians working in tourism and farming. Thousands more lack the proper documents to be in Portugal.

A housing crisis has also fired up debate. House prices and rents have been soaring for the past 10 years, due in part to an influx of white-collar foreigners who have driven up prices.

The problem is compounded by Portugal being one of Western Europe's poorest countries. The average monthly salary last year was around 1,200 euros ($1,882 Cdn) before tax, according to the statistics agency. The government-set minimum wage this year is 870 euros ($1,363 Cdn) a month before tax.

What happens now?

Portugal's head of state convened the country's political parties for consultations.

President Marcelo Rebelo de Sousa, who has no executive power, was consulting with parties before inviting the election winner to form a government, in line with the constitution.

In Lisbon, some residents worried what Chega's surge could mean for democracy, comparing the party to U.S. President Donald Trump's government.

Antonio Albuquerque, 65, said it was the first time in his life he had not voted, because he did not trust any parties.

"Look across the ocean and see if there is a risk or not. What is Trump doing? I think we are in danger, right?" he said.