SYDNEY, Sept 21 (Reuters) - Hundreds demonstrated in locked-down Melbourne on Tuesday after authorities shut down construction sites in the city for two weeks saying the frequent movement of workers was spreading the coronavirus into regional areas. The decision to halt building activities comes after an anti-vaccine mandate protest in the city turned violent on Monday. The Victorian government requires all construction workers to have at least one vaccine dose by end of this week. "The public health team was left with no choice but to hit the pause button and continue to work with the sector over the next two weeks to improve compliance ... and slow the spread of the virus," state Health Minister Martin Foley told reporters. Footage on television and social media showed protesters marching through the city"s streets, setting up flares and chanting, with mounted police and officers in riot gear following them. The forced closures of construction sites will worsen the country"s economic activity with some economists predicting the extended lockdowns may push Australia"s A$2 trillion ($1.45 trillion) economy into a second recession in as many years. Australia has locked down Sydney and Melbourne, its largest cities, and the capital Canberra to quell an outbreak of the highly infectious Delta variant. But these tough restrictions have triggered anti-lockdown rallies with police arresting hundreds in both cities over the weekend. read more A total of 603 new cases were detected in Victoria on Tuesday, the year"s biggest daily rise, eclipsing the previous high of 567 a day earlier, and one new death was recorded. Authorities, meanwhile, have begun to ease some tough restrictions on outdoor gatherings and exercise in Sydney and Melbourne as vaccination rates surge, with more freedom promised once dual-dose levels in the adult population reach 70%-80%. So far, 53% in New South Wales state, home to Sydney, have been fully vaccinated while the coverage is 44% in Victoria. New South Wales reported 1,022 new infections, the majority in state capital Sydney, up from 935 on Monday, and 10 deaths. Even with the Delta outbreaks, Australia has kept its COVID-19 numbers lower than many comparable countries, with 88,700 cases and 1,178 deaths. ($1 = 1.3780 Australian dollars)