Extreme heatwave wreaks havoc on Aussie sporting schedule

On Thursday, Australia faced its third consecutive day of record-breaking heat that's exacerbating an already catastrophic situation for many states.

A state of emergency was declared in New South Wales as bushfires and extreme heat wrecked devastation across the state.

While firefighters tirelessly battle the ever-growing menace of deadly bushfires, the sporting landscape has been thrown into chaos around the country, with more scorching temperatures expected.

New Zealand have taken the drastic measure of abandoning the opening day of their warm-up game ahead of the Boxing Day Test against Australia because of sweltering conditions forecast for Melbourne.

Team management cancelled Friday's play on player welfare grounds because of a predicted maximum temperature ranging from 43C to 45C.

The match against a Victoria XI at Scotch College, scheduled for Friday and Sunday, will become a one-day first class match.

New Zealand were forced to postpone the opening day of their tour match due to extreme heat predicted for Melbourne on Friday. Pic: BOM/Getty

Coach Gary Stead confirmed the tourists will rest on Friday, train at the MCG on Saturday morning, before batting first in the reduced match.

"If it's going to be that hot, I'm not sure we're going to get too much out of it," Stead said on Thursday.

"And there's just the danger element as well."

A week out from the Boxing Day Test, Stead said the rest would be timely for a team still recovering the stifling heat of the first Test in Perth, albeit that it finished in defeat inside four days.

"It's hard to underestimate the effect that Perth had on us," Stead said.

"We were in 40C temperatures every day. The travel back from Perth to Melbourne's pretty gruelling as well, and guys are still struggling to get their sleep patterns right.

"Having the extra day shouldn't do any harm to us."

Stead remained highly confident key quick Trent Boult would be fit for the MCG, having sat out the Optus Stadium Test with an intercostal muscle injury.

Boult bowled with few problems at a training session on Wednesday.

"He looked somewhere near back to his best and was really confident running in," Stead said.

"So that was pleasing to see and he's certainly on track to be available for the MCG Test."

Extreme heat throws racing industry into turmoil

The horse racing industry has also been throw into disarray by the extreme heat with a number of schedules meets postponed or abandoned due to the scorching temperatures around the country.

South Australian racing officials have decided to push back a pre-Christmas race meeting at Morphettville because of the intense conditions.

A twilight race meeting was scheduled for Morphettville on Friday but the seven races have now been moved to Monday afternoon.

A meeting at Dubbo in NSW on Saturday has been abandoned because of a predicted 45 degrees and no suitable alternative dates available.

Saturday's Sydney metropolitan meeting has been moved from Warwick Farm in the west to Randwick which is expected to be up to 10 degrees cooler.

Racing officials in NSW, Victoria and South Australia have been juggling start times of recent meetings to try to avoid the hottest parts of the day.

AFL clubs have also been sweltering during pre-season training, with many players baking in temperatures nearing a maximum of 40C in the Victoria capital on Wednesday.

With AAP