Hong Kong's democrats romped to a landslide and symbolic majority in district council elections after residents turned out in record numbers on Sunday to vote following six months of anti-government protests in the embattled city.

In a rare weekend lull in the unrest that has rocked the financial hub, democratic candidates across the city of 7.4 million people secured more than half of the 452 district council seats for the first time against a strongly resourced and mobilised pro-establishment opposition.

When the results began trickling in after midnight, including upset wins for democrats against heavyweight pro-Beijing opponents, some voting centres erupted in loud cheers and chants of "Liberate Hong Kong. Revolution Now" - a slogan used by many protesters on the streets over the past six months.

Some winning candidates said the result was akin to a vote of support for the demonstrators and could raise the heat on Hong Kong's pro-Beijing chief executive, Carrie Lam, amid the city's worst political crisis in decades.

"This is the power of democracy. This is a democratic tsunami," said Tommy Cheung, a former student protest leader who won a seat in the Yuen Long district close to China's border.

The voting ended with no major disruptions in a day that saw massive, though orderly, queues form outside voting centres.

Pro-democracy candidates had secured a clear majority by 8.00 a.m. (midnight GMT Sunday) with 333 of 452 seats, compared with 52 for the pro-establishment camp, according to media estimates. Democrats only secured around 100 seats at the previous polls four years ago.

Almost three million people voted, a record turnout of more than 71% that appeared to have been spurred by the turmoil, almost double the number last time.

Hong Kong's district councils control some spending and decide a range of livelihood issues such as transport. They also serve as an important grassroots platform to radiate political influence in the China-ruled city.

"Path of struggle"

"I believe this result is because there are a lot of voters who hope to use this election and their vote to show their support for the (protest) movement, and their five demands, and their dissatisfaction with the Hong Kong government," said former student leader Lester Shum, who won a seat.

The protesters' demands include full democracy, as well as an independent inquiry into perceived police brutality.

"The district council is just one very important path of struggle. In future, we must find other paths of struggle to keep fighting," Shum said.

The state-run China Daily newspaper said in an editorial on Monday the election "will hopefully have served as an opportunity to return the city to normal".

"The relative tranquility the city enjoyed since several days before the election suggests all stakeholders regarded it as an opportunity to air their views."

Demonstrators are angry at what they see as Chinese meddling in the freedoms promised to the former British colony when it returned to Chinese rule in 1997. They say they are also responding to perceived police brutality.

China denies interfering and says it is committed to the "one country, two systems" formula for the autonomy of Hong Kong put in place in 1997. Police say they have shown restraint in the face of potentially deadly attacks.

Jimmy Sham, a leader of the Civil Human Rights Front, which organised some of the anti-government rallies, won his electoral contest, as did Kelvin Lam, who stood in after prominent activist Joshua Wong was barred from running.

A number of pro-Beijing heavyweights including Junius Ho, whose abrasive public comments have made him a hate-figure among many protesters, lost to pro-democracy challengers. He described it on Facebook as "an exceptional election, and an unusual result".

The protests started over a now-withdrawn extradition bill that would have allowed people to be sent to mainland China for trial but rapidly evolved into calls for full democracy, posing the biggest populist challenge to Chinese President Xi Jinping since he came to power in 2012.