Victoria's emergency services fear the weather forecast for this week could rival the conditions of Black Saturday.
209 people died in the fires on that day on February 7.
Northerly winds are expected to strengthen on Monday night with gusts of up to 150km/h on Tuesday followed by a strong south-westerly wind change that is forecast to continue until Wednesday.
Authorities have advised schools may have to close on Tuesday, depending on fire risk assessments, while travel and recreational plans in high-danger areas should be reconsidered.
Emergency Services Commissioner Bruce Esplin said the predicted conditions were serious.
"The weather forecast is for conditions that could approximate Black Saturday or Ash Wednesday," Mr Esplin told a briefing on Sunday.
Country Fire Authority (CFA) crews are battling blazes at Wilsons Promontory, Bunyip, and two Kilmore-Murrindindi complexes.
The total area burnt from the four fires so far is 302,875 hectares.
A spokesman for the Department of Sustainability and Environment Craige Brown said the Kilmore East-Murrindindi North fire could breach containment lines on Tuesday.
CFA chief officer Russell Rees said additional resources had been committed from Monday night to prepare for increased fire activity.
He said: "History shows that fires that start in the night cause the most confusion and the most difficulty. To wake up in the morning to have fire around and on your doorstep is a terrifying thing."
Fire plans should be activated early on Monday to avoid panic and traffic congestion on the roads in the event of fire outbreaks, Mr Rees said.
Police will suspend searches for people missing from the February 7 bushfires disaster on Tuesday due to safety concerns for members, Victoria Police assistant commissioner Steve Fontana said.