A road test of the website by Journal reporters found that their homes were undefendable because they didn't meet minimum space requirements.

The homes were in a range of environments, including outer-suburban Boronia, outlying rural areas and the Dandenong Ranges.

The kit assesses properties according to the types of vegetation up to 100metres from the home, surrounding slopes and the distance to the closest property boundary.

For the Boronia home, a minimum property distance of at least 56metres was required to be defendable by fire. The Dandenong Ranges home needed 100 metres.

According to the new six-tier fire danger ratings, occupants of undefendable homes in bushfire-prone areas are advised to leave early on severe-danger, extreme-danger and code-red days.

Asked if refuges would be available for evacuees, a State Government spokesman said: "People will need to make their own arrangements as has previously been the case."

Dave Baker, CFA safety manager for the Western Port region, said residents would be given at least three days notice of code-red days to enable them to make arrangements to relocate.

"The issue of relief centres is for local governments to establish. But people need to think about self-sufficiency when they relocate."

Other factors to consider were whether there were water pumps, an independent water supply, whether the home was properly constructed and whether the occupants were capable of fighting a fire.

Harkaway residents group president Darren Batchelor said the website showed that if people were going to stay and defend, they needed to be well prepared.

"It's a personal choice. Most established properties wouldn't have a clear 10-metre zone.

"I'd urge all property owners to try the site and also consider the resources they should need to try to defend a bushfire."