Australian Open organisers insisted on Thursday that their Covid-19 protocols have been “really successful” despite some top players pointing to lax testing at the first grand slam of 2022.

Frenchman Ugo Humbert has tested positive and world No.3 Alexander Zverev of Germany believes there is probably more contagion going undetected.

The tournament director said all players had to test on arrival, then again between day five and seven of the January 17-30 competition whose start was overshadowed by the deportation of unvaccinated men’s world No.1 Novak Djokovic.

“On top of that there’s mandatory symptom testing and every single day each player is provided with an antigen kit that they can pick up at the hotel or here on site,” Craig Tiley told Australia’s Channel 9.

“So far it’s worked well and it's been really successful.”

However, two-time grand slam winner Garbine Muguruza also spoke of slack protocols, saying testing was optional at the Melbourne Park major with results not regularly monitored.

“I test every two days by myself in my room,” the Spaniard said on Thursday. “It’s not mandatory. I still do it.”

Greek Stefanos Tsitsipas, ranked fourth, said it was the athletes’ responsibility. “I have been trying to get a few antigen tests and rapid tests to see whether or not I’m positive, which is a responsibility that I have. It’s something that I have to do in order to see if I'm 100 per cent,” he added.

Australia on Thursday reached 2 million cases in the pandemic, though deaths have been relatively low by international standards at just over 2,900.

“Right throughout the year, the players have been travelling around the world and there have been protocols they have been following that have enabled them to do that,” Tiley added, saying Australia’s protocols were even more rigorous.

Under its “safe player” protocols, Tennis Australia provides rapid antigen kits to players and testing clinics are open for extended hours on site, and at the player hotel.

All players at the Australian Open have to be vaccinated or have a medical exemption — a rule central to the deportation of the unvaccinated Djokovic. Players also had to complete a mandatory PCR test when they landed in Australia and again between day five and seven, a timeframe that would now be over for most of them.