The service, open to the public, is likely to be broadcast live on TV. All Australians are being asked to observe a minute's silence at noon on the anniversary, to pay their respects to the 173 people who died.

Prime Minister Kevin Rudd has declared February 7 a national day of mourning, with the Australian flag to be flown at half-mast on official buildings.

The National Council of Churches is encouraging all religious denominations to incorporate commemoration of Black Saturday in normal services over the anniversary weekend.

The St Paul's service is being organised by the Victorian Council of Churches and the Bushfire Reconstruction and Recovery Authority. Premier John Brumby said it was being held ''to give those who lost loved ones in the disaster, and those who may not want to return to affected communities, an opportunity to remember and reflect''.

''The one-year anniversary of the fires will be an incredibly difficult and emotional time, and a range of private community gatherings are being planned across affected areas to commemorate the day,'' he said.