A wild storm with heavy rain and lighting has unleashed chaos across Sydney, sparking major delays on the roads and disrupting flights.

The freak weather incident battered the city more than an hour on Sunday evening, dumping about 20 millimetres at the airport.

Several flights were cancelled or delayed at Sydney Airport, causing frustration and mayhem for hundreds of passengers.

The Nine Network aired footage showing the storm hitting Sydney, and describing it as “like a wall of water” as it approached.

The weather bureau warned there could be more storms in coming days.

“Severe thunderstorms in the warning area have temporarily eased,” the Bureau of Meteorology said.

“However, the redevelopment of severe thunderstorms remains possible.

“The situation is being closely monitored and further detailed warnings will be issued as necessary.”

Bushfire evacuations

Meantime, up to three homes have been destroyed by fire and holiday makers evacuated from popular tourist spots along the Great Ocean Road, as out-of-control bushfires rage in western Victoria.

Some 80 bushfires and grassfires ignited in hot conditions on Saturday and hundreds of firefighters are racing to contain two that are burning out of control.

One is at Kadnook near the border with South Australia and the other is threatening communities along the Great Ocean Road, a major tourist drawcard in the state’s south-west.

Authorities evacuated campers and hikers from Otway National Park as they closed walking tracks. The park shut for about six hours overnight over concerns about smoke and fire.

The fire Kadnook, Victoria, where at least one home was destroyed. Photo: Forest Fire Management Victoria

The blaze at Chapple Vale has ripped through about 700 hectares, with anyone still nearby told to leave immediately including those in Crowes, Gellibrand Lower, Johanna, Johanna Heights, Lavers Hill, Stalker, Wangerrip, Wattle Hill and Yuulong.

“Don’t wait, leaving now is the safest option — conditions may change and get worse very quickly,” an alert from the Vic Emergency website states.

“Emergency services may not be able to help you if you decide to stay.

“By choosing to stay, you and your family may be at risk of serious injury or death.”

Out-of-control bushfires rage in western Victoria. Photo: Seven Network

The fire at Kadnook claimed one home and authorities believe two others may have been burnt down, on top of stock and agricultural losses.

The fire is ripping  through rough terrain so water-bombing aircraft were used to attack the flames, which CFA Chief Officer Jason Heffernan said had destroyed 1000 hectares at a private bluegum plantation.

“[It is] quite undulating country, which will be challenging for firefighters to be able to get in there and get containment around it,” he said on Sunday.

The cool change has kicked in but there is now a concern lighting and strong winds could flare fire conditions.

BOM issued a severe weather warning for damaging, locally destructive winds and heavy rainfall for parts of Victoria’a south-west coast and north-east.

“It’s definitely concerning that we have seen lightning through that part of the state where we have obviously seen fire conditions already, and with the elevated westerly winds this afternoon it is going to pose an impact,” senior meteorologist Keris Arndt said.

There were more than 200 requests for assistance to the SES in the 24 hours to 10am on Sunday, including about 70 in Shepparton in central Victoria related to trees and powerlines down in storms.