Pan-democratic parties flocked to the election watchdog yesterday to lodge more complaints about the records of over 550 voters with suspicious or false residential addresses, warning they could be "the tip of the iceberg". A flood of cases reported to the Registration and Electoral Office recently included complaints by residents of unknown people registering their home addresses for voting in the district council elections in November. Among new cases yesterday were voters registering addresses that do not exist, and seven or eight voters registering as living together in flats of 200 to 300 sq ft. In one case a voter claimed to be living in a hospital. Mak Tak-ching of the Labour Party, who led colleagues to file 300 cases to the office, said such irregularities were widespread in constituencies including Tsuen Wan, Hung Hom, Sai Wan Ho and Ma On Shan. "We believe it is only the tip of the iceberg. The electoral office should take it seriously and proactively launch an investigation," Mak said. Democratic Party community officer Winfield Chong Wing-fai, whose party reported about 50 suspected vote-planting cases, accused the office of laxity. "There is one case of a voter who registered a power distribution transformer station as the home address. This could not have been accepted in the first place if the office was serious about its work," said Chong. The Post has previously reported on voters claiming they live in hotel rooms, the Cultural Centre, Tsim Sha Tsui, and parks. Civic Party lawmaker Claudia Mo Man-ching warned that such irregularities could erode confidence in the election system. Yesterday was the last day for voters to check and update their particulars in order to vote in November, and for the public to report suspicious cases. An office spokesman said all complaints would be handled in accordance with the law. A person who gives false or incorrect information in making a voter registration may face up to six months in jail and a HK$5,000 fine. Scores of people were convicted of registering false addresses in 2011. The district council elections will be held on November 22. It will be the first general elections since the Occupy protests and the pan-democrats' rejection of the government's proposed reform for the 2017 chief executive election. The polls are seen as a key test of voters' reaction to the pan-democrats' tactics. Meanwhile, the Privacy Commissioner reminded candidates not to use voters' personal data for electioneering activities without their consent. Since 2012 the office has received 200 complaints about such election-related offences. It said the data should be destroyed after completion of all the electioneering activities.