The Australian military will help enforce the quarantine of travellers returning to the country, with the prime minister announcing strict new measures and door-to-door checks on Friday to rein in the spread of Covid-19. With two-thirds of Australia’s 3,000 Covid-19 cases still linked to overseas travel, Scott Morrison said 14-day home quarantines would be actively policed with the help of the military. Thousands of citizens and residents are still arriving in Australia every day and there have been instances of return travellers repeatedly breaking a promise to stay at home. Morrison said all returnees arriving after midnight Saturday would be kept in hotels in the city of arrival for the duration of their quarantine. Those already on Australian soil and under orders to self-quarantine for two weeks would face active checks, he said.