Hong Kong voters went to the polls Sunday in legislative elections seen as a crucial test for the Beijing-backed government, as calls for full democracy grow and disenchantment with Chinese rule surges.

Nearly 3.5 million people are eligible to cast ballots in the poll, which comes after weeks of protests against a plan to introduce Chinese patriotism classes into schools forced the government into a last-minute climbdown.

Voting began at 7:30 am (2330 GMT Saturday) and will continue until 10:30 pm with results not expected until Monday.

The new legislature could pave the way for universal suffrage in 2017 for the job of chief executive and by 2020 for the parliament.

Forty of the 70 seats -- expanded from 60 in the outgoing assembly -- will be directly elected, the first time that more than half of the seats in the Asian financial centre have been decided by popular vote.

The remainder are chosen by relatively small "functional constituencies" of electors grouped along economic and professional lines, including wealthy business leaders with strong financial ties to the mainland.

Besides the protests over education policy, tensions have been brewing over corruption, the yawning gap between rich and poor, soaring property prices and the strains of coping with an influx of millions of mainland tourists.

Surveys show dissatisfaction with mainland rule is rising, especially among the young, while satisfaction with the Communist Party's performance in governing China is at its lowest point since the 1997 handover from Britain.

Pro-democracy parties have seized on the education furore to galvanise their supporters, hoping to win the minimum 24 seats they need to retain a veto over constitutional amendments required for the introduction of universal suffrage.

They fear Beijing will try to force through a sanitised version of universal suffrage that gives the central authorities power to screen candidates.

Organisers of the campaign against national education said protests outside the government headquarters swelled to 120,000 people on Friday, and 100,000 people on the eve of the vote. Police put the number at 27,500 on Saturday.

Critics of the policy said it amounted to brainwashing, citing state-funded course materials praising the benefits of one-party rule.

In an unexpected U-turn late Saturday, Chief Executive Leung Chun-ying held a news conference to announce that a 2016 deadline for the curriculum to be taught in all primary and secondary schools had been dropped.

But analysts said the bid to defuse the education row might come too late to help pro-establishment parties at the ballot box.

"The anger has been building up for the whole week, and it's not going to die down overnight," Chinese University political scientist Ma Ngok was quoted as saying by the South China Morning Post newspaper.

Voter William King, a 65-year-old businessman, said he would cast his ballot for those who stood up against the education policy.

"This is a vote against national education. We want to vote for those who can push for democracy in Hong Kong," he told AFP as he voted with his wife and daughter.

Beijing-backed newspaper Wen Wei Po described the pro-democracy camp as people who "throw bananas", an apparent reference to the protests and the noisy antics of some radical lawmakers.

"The voters should make good use of the ballot in their hands and punish the candidates who are 'destructive'," the paper said in an editorial Sunday.

Hong Kong was ruled as a colony of Britain until 1997, when it was handed back to China as a semi-autonomous territory with broad rights and freedoms.