"I had yesterday off and I went to the plaza and there were a lot of people there," the Mildura Working Man's Club receptionist said.

Being the town's only airconditioned shopping centre, Ms Telfer wasn't the only one to seek refuge there from the sweltering heat that blanketed the region this week.

A spokeswoman from Vicinity Centres, which manages the plaza, said the shopping complex "was attracting plenty of visitors to escape the heat".

Mildura sweated through its hottest consecutive days on record on Thursday and Friday, with the mercury reaching 46 degrees.

Bureau of Meteorology forecaster Stuart Coombs said never before has Mildura experienced two days of 46-degree heat in a row.

"There were two 45-degree days on February 14 and 15 in 2004, but this is the first time we've had a pair of 46s," he said.

The thermostat it set to soar again today, with a predicted high of 41 degrees.

"Today along the Murray River we're expecting the highest temperatures," he said. "Along that strip we can expect some of those locations to reach 40 degrees, including Mildura, Swan Hill, Echuca, Wodonga and Yarrawonga; that's where the maximum heat is likely to be."

Mr Coombs said mid-level cloud and a couple of thunderstorms over the region had interrupted the temperature rise.

Even if a storm does eventuate, there won't be much rain with it.

The fire danger rating isn't expected to be raised to severe or extreme despite the heat, due to high humidity and little wind.

Brendan, who works at the Mildura Brewery Pub, said even the town's hotels have been relatively quiet.

"Some people have come out to have a few beers but most are trying to stay as cool as possible, they're all congregating up at the plaza," he said.

"This end of town is a ghost town."

Meanwhile Victoria's northern neighbours are facing a threat of blackouts on Saturday as an extraordinary heatwave envelopes New South Wales.

The Australian Energy Market Operator has issued an alert for a potential lack of power reserve in NSW for two periods on Saturday afternoon and evening.

The sizzling conditions have already pushed the state's energy network to the limit, with demand for power among the highest on record.

NSW managed to dodge widespread power blackouts on Friday, but households and businesses again have been asked to curb their power use throughout this weekend.

The warning comes on a day the mercury is forecast to climb to a top of 39 degrees in the Sydney city and a sweltering 46 degrees in Sydney's outer west and the state's north-west.

The abnormal heat could push the mercury to NSW's hottest overall temperature on record for February on Saturday, reaching about eight degrees above normal.

With Megan Levy, Peter Hannam