SEOUL, July 23 (Reuters) - Members of South Korea"s main trade union defied government coronavirus restrictions on Friday to rally in support of demands for better working conditions and pay despite police efforts to block the gathering. South Korean trade unions have a long history of activism but their recent rallies have led to confrontation with authorities trying to enforce curbs to stop the coronavirus. Rallies have been blamed for surging COVID-19 cases in South Korea since an anti-government protest organised by a church last year was widely seen as triggering a second wave of infections. About 400 members of the Korean Confederation of Trade Unions (KCTU) gathered in the city of Wonju, 100 km (62 miles) east of the capital despite a government warning it was illegal because of social distancing rules. Hundreds of police lined up with metal barriers to block the rally outside a government building but the trade unionists surged past to gather in a nearby park, footage from broadcaster YTN showed. Kim Jae-deok, the city"s safety management team chief, told Reuters there were no serious clashes. "The city will file a complaint against the labour group with the police for breaching anti-epidemic guidelines," Kim said by telephone. South Korea reported 1,630 new coronavirus cases on Friday, down from a daily record of 1,842 the previous day, amid rising infections nationwide fuelled by the virulent Delta variant among the unvaccinated. read more The government on Friday extended semi-lockdown measures in Seoul and neighbouring areas, which include a ban on gatherings of more than two people after 6 p.m. Interior Minister Jeon Hae-cheol had earlier warned of stern action against any group holding a banned rally in violation of anti-epidemic rules. Wonju city tightened its restrictions to the highest level with effect from midnight on Thursday, with a ban on rallies but the trade union rejected the restrictions as "baseless". South Korea"s tally of infections stands at 185,733, with a death toll of 2,066, official data showed. The vaccination rate remains low, with just over 13% of the 52 million population fully vaccinated, while the government aims to reach herd immunity before November.