UPDATE: FIREFIGHTERS hope easing weather conditions will help them in their fight against blazes in south west Victoria tonight.

A State Control Centre spokeswoman said crews were battling 12 fires which were believed to have been started by lightning strikes overnight in the Casterton and the Little Desert area.

At 4pm today, she said all but one fire was contained.

The B-Line Track fire, about 18km west of Casterton, has burnt 1660ha of land and authorities hope easing weather conditions will help them bring it under control tonight.

She said DSE had 75 staff, CFA six members and 43 other personnel were tackling that blaze.

Six fixed wing planes and helicopters are working in the region.

Fires on the Little Desert East Track reached 215ha in size and the Little Desert – Lillimur Track are said to be 210ha in size.

CFA deputy chief fire officer Joe Buffone described the area where the fires were as rugged terrain.

"It's very dry . . . and is being fanned by strong wind."

He said crews wanted to get the fires under control before the weekend's forecast warm weather.

Mr Buffone said the fires should act as a warning for people to check their bushfire plans.

He said yesterday weather change started 12 fires in Victoria and about 300 in South Australia.

There are several road closures in the area.

Smoke is visible in communities across the west of the state and in Melbourne this morning.

Advice messages for the blazes say fire spotting aircraft are working in the area and residents should continue to monitor the situation via  ABC local radio or the Victorian Bushfire Information Line 1800 240 667.