Vietnam will slash the duration of mandatory quarantine for foreign visitors from two weeks to just seven days, the health ministry has said, as the Southeast Asian country battles its biggest Covid-19 outbreak yet.

The country's borders closed last year to all visitors but returning Vietnamese citizens, foreign experts, investors or diplomats, all of whom were subject to 14 days of quarantine at centrally-managed facilities, Reuters reports.

Foreign visitors who have tested negative for Covid-19 within 72 hours and have also been fully vaccinated would be permitted to quarantine for seven days, the ministry says.

Vietnam has reported a total of 174,000 coronavirus cases and 2,071 deaths, most of which were recorded over the past month in Ho Chi Minh City, the epicentre of the outbreak.