Australia’s second-most populous city reintroduced coronavirus restrictions after an Australian Open hotel quarantine worker tested positive for Covid-19, sending more than 500 tennis players and officials into isolation.

Melbourne returned to mandatory masks indoors and a cap on gatherings to 15 people after the state’s run of 28 days of zero local infections came to an end, Reuters reported.

Play at the six warm-up events for the Grand Slam at Melbourne Park, due to start February 8, was heavily disrupted with organisers Tennis Australia cancelling all matches for Thursday.