The Country Fire Authority (CFA) is concerned that an expected wind change later this week could cause a large grass fire north of Melbourne to flare out of control.
The blaze has burned about 620 hectares of grass near Seymour.
It is thought it was started by lightning strikes on Saturday night.
The CFA's incident controller, John Leben, says the fire has been contained, but a north-westerly wind change on Wednesday could push it rapidly to the east.
Crews are continuing to reinforce containment lines this morning.
Mr Leben says the fire should act as a serious warning to people who live in high fire risk areas.
"The community needs to be aware that they should prepare for fire on an ongoing basis," he said.
"They should have their fire plans in place, not just for today but for every day of the fire danger period and that includes for the rest of this summer."
© ABC 2012
19:53 EDT Wind gusts of up to 90 kilometres an hour brought down power lines, cut traffic lights and delayed public transport across Sydney this afternoon.