Smoke from NSW's bushfires is covering Melbourne

Smoke from the New South Wales bushfires has made its way south, covering the city and giving Melbourne a taste of the conditions that have been choking Sydney.

Smoke extended over Victoria this morning and into the afternoon from the NSW's fires and the Gippsland fires – in Victoria's south-east - reducing visibility to about 1km in places, the Bureau of Meteorology said.

"The smoke will gradually disperse over the next few hours, although generally hazy conditions are expected right across Victoria today."

Much of Victoria is sweltering through extreme heat today, with a statewide total fire ban in place along with health alerts.

Much of the northwest including Mildura and Horsham are forecast to reach 47C, while Melbourne's temperature is set to soar to 44C and remain hot through the evening and night.