The Australian Open tennis tournament in Melbourne will continue but without fans, despite a five-day lockdown ordered on Friday in its host city to control an outbreak of the UK coronavirus strain, officials said. 

Premier Daniel Andrews of Victoria state, which includes Melbourne, said the tennis venue would be considered a "workplace" that can continue to function with limited staff. 

The year's first Grand Slam opened on Monday with limited crowds due to existing virus restrictions, after all players underwent mandatory quarantine. 

Melbourne's five million residents were ordered to stay at home for five days from midnight after a cluster of COVID-19 cases leaked from a quarantine hotel at the city's airport. 

Play was already underway on day five of the event on Friday when the announcement was made, with Serena Williams, Naomi Osaka and Novak Djokovic all due on court.