CFA Chief Fire Officer Russell Rees said the stay and defend policy, under which homeowners remain on their property to protect it from fire, was based on sound evidence.

"It is the application of that policy and a lack of an alternative that we need to work on," Mr Rees told reporters.

"People need to understand that a late departure is the most deadly.

"We have said, and it is clearly evident, that fires can come without warning and very rapidly, and that you may not receive a warning and that you may not have a fire truck at your front gate.

"The (stay and defend) policy has to be to empower people - if you put in a directive policy to people you will get resistance.

"The clear evidence is that the most dangerous place to be is on the road."

He said emergency services had warned last week that Victoria was facing a threat unprecedented in its history.

"The fire service planned for this day - their planning was meticulous and detailed - it was a thorough plan put into place with efficiency and effectiveness, but the fires, as you all know, were enormous," Mr Rees said.

"Our emergency services worked well together and I am enormously proud of their efforts - they did everything possible they could in the circumstances but they are ready, and stand ready, to learn and further improve.

"Our people can hold their heads up high and I ask you to help them to do that."

Victoria Police Chief Commissioner Christine Nixon said some devastated communities, where the fires were believed to have been deliberately lit, would remain sealed from the public while forensic teams carried out their investigations.

"The CFA in some cases have shut the road because of trees falling or fire that may still be occurring, in some cases the roads are damaged, and for us, people have died on the side of the road or footpaths, so we are investigating that and protecting the crime scenes," she said.

"We are trying to clear these locations as fast as we can, but we need to remember these are mothers and fathers, sisters and brothers ... and we need to treat them with dignity in the way that we go about this process."