Australian Open boss Craig Tiley has ruled out delaying the grand slam despite increasing pressure from restive international players furious about being put into hard quarantine.

A member of the broadcast team travelling from Los Angeles was on Sunday announced as a fourth person to test positive to Covid-19 from Australian Open charter flights.

Travellers from two of the flights, including 47 players, are now confined to their hotel rooms for the next 14 days due to the positive tests.

All international players were originally given an exemption to train for up to five hours a day, however, the test results forced the two flights affected into stricter quarantine under Victorian government orders.

The coach of 2019 US Open champion Bianca Andreescu, Sylvain Bruneau, confirmed he was one of the four cases.

Two-time Open champion Victoria Azarenka and Japanese star Kei Nishikori were among players on the Los Angeles flight, while Svetlana Kuznetsova was on the Abu Dhabi charter that was affected.

Defending Australian Open champion Sofia Kenin is also reportedly in hard lockdown.

COVID-19 Quarantine Victoria Commissioner Emma Cassar confirmed the new case on Sunday and said that police presence had been increased at the Open hotels.

She said that training in Melbourne had been put on hold while they waited on the final test results, although all players and their training partners had been cleared of Covid-19.

Cassar said that there had been cases of “challenging behaviour” from some confined players and support staff.

She cited two cases when they opened their doors to have a conversation or shout down the hallway.

“There is zero tolerance for breaches,” she said.

“I had a conversation with Victoria police this morning to ensure we are increasing our compliance and enforcement efforts and there’s zero tolerance for that behaviour.

“It’s low level but dangerous acts that we just can’t tolerate.”

Cassar warned they could be fined up to $20,000 or repeat offenders transferred to the complex care hotel where they have a police officer stationed outside their door.

Some players in hard lockdown are calling for the February 8 Australian Open start date to be pushed back to ensure they have adequate time to prepare.

Swiss player Belinda Bencic isn’t in lockdown but said those who were were at a disadvantage.

“We are not complaining (about being) in quarantine. We are complaining because of unequal practice/playing conditions before quite important tournaments,” she tweeted.

But Open boss Tiley ruled out talk of another date change for the event.

“We are planning on February the eighth … and our intention is to continue with those dates,” Tiley told Nine Network’s Today Show.

He said they would consider adjusting the schedule for the lead-in ATP and WTA tournaments which are due to start in Melbourne on January 31 and February 1.

Players have claimed they were told that only those in close contact with a positive case would have to go into hard quarantine, and not all passengers on the flight.

Romanian world No.71 Sorana Cirstea said she would have skipped the Open.

“If they would have told us this rule before, I would not play in Australia. I would have stayed home,” she tweeted.

“They told us we would fly at 20 per cent capacity, in sections, and we would be a close contact only if my team or cohort tests positive.”

Tiley said players were warned it was one scenario but that the tournament was at the mercy of the Victorian government.

“The determination of who was and who wasn’t a close contact was going to be entirely up to the health department, and they’re doing what they is necessary in order to keep our community safe,” he said.

“We never knew what the situation or decision would be coming in and now we have to manage an environment over the next 14 days for those players who, unfortunately, are not going to have the same conditions of those who are able to get out to practice.”

Tiley said the recent threat of the UK strain of the virus had changed the situation but insisted players knew there was a risk of isolation.

As well as lockdown some players have been slamming the hotel food while Kazakhstan’s Yulia Putintseva saying she’s repeatedly asked to change rooms due to a mouse in hers.

Cirstea said she wants to go home but isn’t allowed.

But the players are getting little sympathy from many Australians, with thousands of compatriots unable to travel home while many Victorians are currently locked out of the state.

The players will pocket a minimum $100,000 if they take part on the Australian Open main draw.