The sudden rise in temperature has prompted time changes for the Werribee meeting to avoid the hottest part of the day.

Monday's meeting at Werribee will begin at 10.30am with the last of eight races at 2pm.

"Following advice from the Bureau of Meteorology that the forecast is expected to reach 42 degrees towards 4pm, the race times have been brought forward two hours to avoid the hottest part of the day," Racing Victoria said.

RV's Racing Operations team will continue to monitor the forecast over the next three days.

A maiden on the program had 29 acceptors, but given the forecast the race was not divided.

Instead a race will be added to the Geelong meeting next Thursday with preference given in the ballot to horses that did not get a run at Werribee.