Forecasts temperatures of 40 degrees in Melbourne has prompted officials to move meetings including the metropolitan Caulfield program.
The nine-race Caulfield meeting will now be moved from Saturday to Sunday afternoon when temperatures are predicted to be 20 degrees cooler, while the seven-race card at Mornington scheduled for Sunday will now be staged on Saturday and brought forward to avoid the hottest part of the day.
Acceptances for the Caulfield meeting will still be taken on Wednesday and Mornington acceptances will also close on Wednesday morning.
"Although a high is predicted of 35 degrees in Mornington this Saturday, the expected sea breeze and low humidity will create a safe environment for horses and participants to compete," a Racing Victoria statement said.
"Mornington race times will be brought forward to avoid the hottest part of the day."
Races at Stawell on Friday will start earlier than planned at 12.30pm and finish at 4pm while decisions on Saturday's meetings at Kilmore and Dederang will be made on Wednesday.
"If the forecast for Kilmore remains around 40 degrees the meeting will be moved to Monday, 8 January to race with Stony Creek, whilst Dederang will be abandoned as there are no suitable replacement dates this weekend," RV said.
"All revised meeting dates and race times have been implemented in accordance with RV's Procedure for Racing in Hot Weather Policy, which is designed to ensure the health and wellbeing of horses and participants is paramount."
South Australian officials have also announced scheduling changes for this weekend's racing because of expected high temperatures on Saturday with the Gawler metropolitan meeting moved to Sunday.
As a result, the Naracoorte meeting on Sunday has been rescheduled to Monday.