Australian Open tournament director Craig Tiley insisted players would not be put in danger amid air quality concerns in Melbourne.
Play was delayed on the opening day of qualifying on Tuesday due to poor air quality caused by bushfires in Australia.
While organisers faced criticism for allowing play to begin, Tiley said players would not be put at risk.
“We reiterated with the players that we’re making a decision based on advice, based on expert advice,” he told a news conference.
“We’re not going to put them in harm’s way or make any decision that’s going to negatively impact their health and wellbeing.
“We have a track record of that when it comes to extreme heat. I think we’re one of the few major events that has to manage extreme heat like we do.
“But this is a new experience for all of us, how we manage air quality and therefore we’ve got to rely on those experts that advise us on how best to continue.”
Slovenian Dalila Jakupovic retired during her qualifier against Stefanie Voegele when leading 6-4 5-6, with reports suggesting she was struggling with her breathing.