TASMANIAN authorities have declared a total fire ban for the northern and southern regions of the state.

Warm weather, strong winds and dry fuel loads mean some of the bushfires burning across the state are unpredictable and difficult to extinguish.

A watch and act alert is in place for an out-of-control blaze near Franklin in the Huon Valley, south of Hobart, with the area on a high fire danger rating and the Collinsvale and Molesworth Primary Schools will remain closed today.

A watch and act alert had also previously been put in place for a fire at Lefroy near George Town, in the state's north, with the area on a low to moderate fire danger rating.

The fire ban today covers Break O'Day, Dorset Flinders, George Town, Launceston, Meander Valley, Northern Midlands, West Tamar, Brighton, Central Highlands, Clarence city, Derwent Valley, Glamorgan, Spring Bay, Glenorchy, Hobart, Huon Valley, Kingborough, Sorell, Southern Midlands and Tasman.