HONG KONG, Dec 19 (Reuters) - Hong Kong people headed to the polls on Sunday, voting in an overhauled "patriots"-only legislative council election that critics say is undemocratic and in which the government is keen to mobilise voting to show the vote"s legitimacy. Some of the first to vote as polls opened at 8:30 a.m. (0030 GMT) said they were keen to do their civic duty to ensure stability in a citythat was rocked by months of sometimes-violent protest in 2019. University language teacher Tam Po-chu, 79, said she hoped the new council would be responsive to the public. "There"s no use if they do not think of the Hong Kong people," she said. Officials have worked to boost turnout, fearing a weak showing could be read as a form of protest against a vote being held without a mainstream opposition party participating, people familiar with the effort have told Reuters. Hong Kong leader Carrie Lam was among the first to vote, telling reporters later that the government "had not set any target" on the turnout rate, and she was not aware of any set by the Chinese leadership. Security was tight around the city, with 10,000 police deployed. Police chief Raymond Siu told reporters before the voting that the mass deployment was to ensure balloting at hundreds of polling stations across the city would be held safely and smoothly. In the run-up to the election, more than 10 people were arrested for allegedly inciting people to cast blank ballots, including people who had reposted social media posts from others, according to government statements. It is illegal in Hong Kong to incite someone not to vote or cast an invalid vote. China"s parliament in March announced sweeping changes to Hong Kong"s electoral system, including reducing the number of directly elected seats and setting up a vetting committee to screen all potential candidates, saying only "patriots" may administer the city. More than a third of the seats will now be selected by a committee stacked with Beijing loyalists. An ongoing crackdown on Hong Kong under a China-imposed national security law has also jailed scores of democrats, while civil society groups have disbanded. Unlike previous polls, pro-democracy candidates are largely absent, having declined to run, gone into exile or been jailed. Some overseas activists and foreign governments, including the United States, say the electoral changes have reduced democratic representation in the city. The Chinese and Hong Kong authorities reject such criticisms, saying the electoral changes and a national security law that took effect last year are needed to enhance the city"s governance and restore stability after mass anti-government protests in 2019. Of the 153 candidates contesting the 90 legislative seats, around a dozen say they are moderates who are not aligned with the pro-Beijing or pro-establishment camp. Hong Kong and Chinese officials have stepped up calls in the run-up to the election for people to vote, fearing opposition to new electoral rules and the absence of democratic candidates will deter voters, some analysts say. Transport operators have also offered free rides on election day. "Clearly, the government"s objective is to secure a high turnout. Otherwise it may delegitimise this election," said Jean-Pierre Cabestan, a professor of political science at Hong Kong"s Baptist University. Chief Executive Lam"s Office and Beijing’s Liaison Office in the city did not did not respond to Reuters requests for comment on voter turnout.