World No.1 tennis player Novak Djokovic has tested positive to COVID-19 and apologised for hosting a tennis tournament which has become the centre of a virus cluster.

The tennis star said sorry for “each individual case of infection” as it was revealed his wife Jelena and his fitness coach had also contracted the virus after three other players previously tested positive.

Social distancing rules were ignored at the charity event in Croatia and video footage later emerged on social media of the Serb star dancing in a Belgrade nightclub with other players.

Australian Nick Kyrios did not hold back with a withering condemnation on Twitter in which he retweeted the video of the shirtless players dancing.

“Prayers up to all the players that have contracted Covid-19,” Kyrgios tweeted.

“Don’t @ me for anything I’ve done that has been ‘irresponsible’ or classified as ‘stupidity’ – this takes the cake.”

Tweet from @NickKyrgios

Djokovic has been criticised for organising the tournament and bringing in players from other countries amid the coronavirus pandemic.

The opening leg featured packed stands, players hugging at the net, playing basketball, posing for pictures and attending press conferences together.

Grigor Dimitrov, Borna Coric and Viktor Troicki tested positive after playing in the Adria Tour exhibition before Djokovic confirmed on Tuesday he and his wife Jelena had returned positive tests after arriving back in Belgrade, although their children have not.

Djokovic’s fitness coach Marco Panichi and Dimitrov’s coach Christian Groh have also tested positive.

“I am extremely sorry for each individual case of infection,” Djokovic wrote in his statement.

“I hope that it will not complicate anyone’s health situation and that everyone will be fine. I will remain in self-isolation for the next 14 days, and repeat the test in five days.”

Tweet from @DjokerNole

Djokovic said he and the organisers has planned the event with a “pure heart” to raise money for players in need while believing it met health protocols and the region was doing well with coronavirus.

“We were wrong and it was too soon,” he said.

The remainder of the Adria Tour has been cancelled.

The tennis professional circuit was halted in early March as nations closed borders and imposed lockdowns to contain the spread of the virus.

Victoria testing ramps up

A new virus testing site will be opened in Victoria as waiting times blew out to four hours amid a worrying spike in infections that has triggered fears of a second wave.

The Melbourne Showgrounds will open at 1pm on Wednesday to Keilor Downs Secondary College students, teachers and parents before opening to the public from Thursday.

The increase in testing comes as Victoria recorded 17 new cases of COVID-19 on Tuesday, doubling the state’s active cases in the past week to more than 130.

Premier Daniel Andrews apologised for the delays at drive-through testing sites at shopping centres, where some people have waited up to four hours to be tested while others have been turned away.

Drivers queued for hours at Melbourne’s Highpoint Shopping Centre for COVID tests on Tuesday.

Testing sites at Chadstone, Highpoint, Northland, Pacific Epping and Pacific Werribee shopping centres have extended operating hours to meet demand.

Meanwhile, the premier said an “army” of officials would begin doorknocking homes in designated hotspots Brimbank, Cardinia, Casey, Darebin, Hume and Moreland to ensure residents are adhering to government guidelines.

Information about the virus will also be provided in languages other than English following concerns COVID-19 messaging hasn’t been reaching multicultural communities in those areas.

“There has been very deep engagement with localised communities, multicultural communities, multi-faith communities,” Mr Andrews said.

Eleven of the state’s new cases are being investigated.

One of the latest cases is a returned traveller in hotel quarantine, three were found in routine testing, and two are linked to a Keilor Downs extended family cluster.

A worker at a Coles distribution centre in Laverton is one of the two family transmission cases confirmed on Tuesday.

Meanwhile, Brunswick East Primary School and Keilor Views Primary School were closed after a student at each school tested positive.

Victoria accounted for most of Australia’s 20 new coronavirus cases on Tuesday with one in NSW and two in WA.

There will also be a close watch on about 800 Australians from South America, India and Indonesia who will fly home from overseas into Adelaide by June 28.

Mystery over AFL player’s positive-negative result

Essendon coach John Worsfold will address the mysterious situation surrounding defender Conor McKenna’s conflicting COVID-19 test results.

Late on Tuesday evening, the Bombers confirmed the defender returned a negative result to his COVID-19 swab test.

But tests taken by McKenna last Friday and Saturday had still shown up a positive result, resulting in the match on Sunday against Melbourne being postponed.

It is another strange chapter to a saga which had threatened to derail the AFL season when McKenna had tested positive over the weekend.

Conor McKenna (centre) and teammates may be in the clear after his result came back negative. Photo: AAP

Worsfold will speak to the media for the first time since the incident unfolded, talking to reporters via at Zoom call about midday on Wednesday.

There were fears several key defenders, including Adam Saad, Cale Hooker and Michael Hurley, would be forced to quarantine after taking part in a weights session with the Irishman.

 -with AAP