TOMORROW is a total fire ban in Victoria's Mallee and Wimmera.

The CFA this afternoon said the restrictions start from midnight tonight.

Mildura is tipped to reach 44C, Kerang 42C and Horsham 42C tomorrow.

The fire bans come as the authority warned farmers to be aware of the risks of harvesting in hot weather.

CFA District 2 operations manager Mark Gilmore said farmers or contractors harvesting needed to take regular breaks to clear grass, sticks and seeds from airflow vents, stone guards and bash plates of machinery.

"On top of that don't forget to regularly look behind you- hot exhausts can easily start fires as can sparks when machinery hits stones," he said.