Thousands of children will be affected by the closures in southeast Victoria state, which is bracing itself for a deadly combination of searing temperatures, strong winds, and tinder-dry countryside.

Nearly 200 government schools and 146 children's centres will be closed as a precaution because fire authorities have warned of "extremely difficult weather conditions," Victorian Education Minister Bronwyn Pike said.

Temperatures of 39 degrees Celsius (102 degrees Fahrenheit) are expected across the state on Friday, raising fears that the heat and wind will stoke five major fires still burning or that lightning will start new ones.

Three schools burnt down on "Black Saturday" -- February 7 -- when temperatures of up to 46 C combined with high winds to raze more than 2,000 houses and kill a total of 210 people.

"This certainly is an extreme set of circumstances. We've got a tinder-dry environment and existing fires. The risk is very great on Friday," Pike said.

On Thursday, a heavy pall of smoke drifted across the eastern suburbs of the capital Melbourne as more than 3,000 firefighters worked on building defences against Friday's feared conflagration.

The authorities warned residents threatened by the fires to decide early whether to leave their homes or stay and try to defend them.

"Don't leave it too late in the day when you can see fire. Make that decision very early and make it a very conservative decision," said state emergency services commissioner Bruce Esplin.

"If you're not prepared physically and psychologically then it is better to be away from that area."

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.