Storms packing powerful winds toppled trees, killed one person and knocked out power to hundreds of thousands of homes and businesses in eastern Australia, officials said Wednesday.

The wild weather hit large swathes of Victoria on Tuesday, dumping torrents of rain and unleashing some gusts of more than 150 kilometres per hour (90 miles per hour), officials said.

A 50-year-old dairy farmer was killed in the storm, apparently struck by flying debris while on a tractor east of Melbourne, officials told a news conference.

The winds also propelled bushfires in the Grampians region west of Melbourne, burning an unknown number of homes in one small town, they said.

At its peak, 530,000 homes and businesses lost power, the Australian Energy Market Operator said in an update.

Some 285,000 were still cut off on Wednesday morning, it said.

"Given the extent of the widespread damage, it may take days if not weeks to restore electricity to all of those impacted," the authority said.

The winds tore off roofs, uprooted trees and flattened electricity pylons, according to media reports and images shared on social media.

Fallen transmission towers led to the shut-down of Victoria's largest electricity generator, the coal-powered Loy Yang A, which is now being reconnected to the grid, the state's energy authority said in a statement.

"This has been one of the largest outage events in the state's history," Victoria Energy Minister Lily D'Ambrosio said.

Lightning strikes ignited "multiple fires" in Victoria, said the state's emergency management commissioner, Rick Nugent.

In the hard-hit Grampians region, flames incinerated "a number of residential homes" in Pomonal, home to a few hundred residents, Nugent told a news briefing.

It was too early to say how many homes were affected, he said.

The authorities said they were working to restore power and ascertain the full extent of fire damage as bushfire and weather warnings were lowered across the state.