An extra 6,000 bottles of water – and 20,000 cups of beer – have been ordered to keep a capacity crowd cool at Sunday’s NRL and NRLW grand finals double header in Sydney, which is forecast to be the hottest ever.The expected record temperature for the traditional conclusion of the winter codes comes amid warnings for more hot weather over summer as sport feels the effect of the climate crisis.

The Bureau of Meteorology’s temperature forecast for Olympic Park on Sunday was 36C, which would make it the hottest for any previous grand final day. The temperature on the day of the 2014 NRL premiership decider when South Sydney triumphed over the Bulldogs reached 34.7C.

On Sunday, the State Championship between Brisbane’s Easts Tigers and Souths’ NSW Cup-winning side kicks off at 1.20pm, before the NRLW grand final between Newcastle and Gold Coast at 3.55pm. The men’s NRL decider starts at 7.30pm.

The NRL’s head of elite football, Graham Annesley, said on Monday that “without being dismissive of the weather bureau, things can change”. He said there were “levers” that could be pulled if the conditions were deemed too dangerous by the league’s assessment of temperature, humidity and other factors, including the possibility of changing kick-off times. “We are ready for any circumstances, as we are throughout the whole season,” he said.

A spokesperson for Accor Stadium said they were mindful of the heat and were taking extra precautions. “We’re telling people to prepare for the hot weather. So wear a hat, wear sunscreen, sunscreen will be available at all the food outlets and just stay hydrated.”

The venue’s food outlets increased their stock of water bottles from 24,000 to 30,000, and beer consumption was expected to go from 100,000 to 120,000 cups. Patrons can bring their own non-glass water bottles and refill them at any food outlet.

Coach of the Easts Tigers, Matt Church, said his team was used to playing in hot and humid conditions, including two fixtures early in the season above 35C, but it required players to ensure they were hydrated even before game day. “Fatigue sets in a lot more and the concentration level really goes, so you’ve got to make sure that you’re hydrated, otherwise it can really bring you undone,” he said.

The game marks the formal transition from the winter codes to summer sport, dominated by cricket, tennis and elite football. The Bureau of Meteorology updated its long-range forecast last week. “October to December maximum temperatures are at least three times as likely to be unusually warm for most of Australia,” it said.

Sport New Zealand invited the chair of the country’s Climate Change Commission, Dr Rod Carr, to provide a keynote for its high-profile Connections 2023 conference in July. Dr Carr warned outdoor events are likely to be disrupted more often in the future. “You need to accept that and plan for it rather than hope it won’t happen to your event on the day,” he said. “Hope is not a strategy.”

Church said the rugby league “product” suffered if it was played in high temperatures. “When it gets hot, the ability to make the correct decisions is more challenging,” he said. “Hanging on to the ball, obviously perspiration and we play with a rubber ball it can sometimes get a bit greasy and slippery.”

The Australian Sports Commission is developing guidelines relating to smoke pollution and exercise and is expected to release them ahead of the summer bushfire season.

Dr Troy Cross, senior lecturer in exercise and sports science at University of Sydney, said smoke was a problem for many athletes, but the science around bushfires and sport was still emerging, and it was hard to provide general advice when the effects of one bushfire could be different to another based on the wood that burns.

He said elite athletes tended to exercise more intensively and more often than others, but also appeared to be more at risk. “We see a lot more people [at elite level of sport] who have asthma or airway hyper-responsiveness, more so than the general population. And this is a population that’s quite sensitive to the composition of air we breathe.”