Asked his strategy, Mr Shirreff, 47, of West Footscray, echoed the advice of canny shoppers and centre managers, with just Monday left to buy Christmas gifts: get there early and have a plan.

Mr Shirreff said he and his wife, Nicole, 45, and son Corben, 15, arrived at 9.15am. They found a parking spot easily. By the time they returned to their car around 1pm, they were being stalked by drivers desperate for a park.

"There were people everywhere."

Mr Shirreff knew what he wanted to get for each family member. Unfortunately "the plan flew out the window" as they were distracted by one shop after another.

The family returned to one outlet four times to find exactly the right handbags for twin daughters Natae and Tamsyn, 17, who weren’t with them.

"They’re bargain hunters and they couldn’t decide so between them and their mum, Facetiming each other and trying to decide, I ended up taking the reins and saying, ‘Come on, this is what you wanted at the start, so let’s get it’."

Corben, however, was easier to please, choosing sports clothes, a basketball bag, headphones and a microphone for his PlayStation.

Fellow shoppers Chris and Nadia David were also early birds, whipping through Highpoint in 90 minutes from about 10am.

They spent $500 to complete their shopping for kids Jessica, 15, James, 10, Mr David’s father and nieces and nephews.

"We’re all done," said Mr David, 47, of Pascoe Vale. He said the family could now concentrate on preparations to host 12 relatives on Christmas Day.

Mr David said knowing beforehand "who to buy for and what to buy" was a time saver and prevented impulse buying.

Management of Highpoint, in Melbourne’s west, estimated 180,000 people will have streamed through that shopping centre in its 32 hours of being open non-stop before closing at 5pm on Monday.

At Chadstone, the customer tally for a 34-hour shopping marathon is estimated at 240,000 until doors close at 6pm on Monday.

Highpoint senior marketing manager Prue Arkeveld said measures used to attract customers included free gift wrapping and free snacks handed out by roving staff.

On Sunday from 5pm to 9pm and on Monday from noon to 3pm, Silver Top Taxis was offering free cab rides from 16 surrounding suburbs to and from Highpoint.

Ms Arkeveld said beach bags and beach towels are proving popular this year, as are retro and interactive toys including LOL Surprise — plastic cases filled with smaller toys — and the Harry Potter range of Lego.

Personalisation — getting your name or initials monogrammed on leather goods and stationery — was also a "massive trend".

Chadstone centre manager Michael Whitehead said peak hour on Monday is expected to be between noon and 1pm, so he advised shoppers to "try to get here as early as you can, and make sure you’ve got your list, ready to go".

For those struggling for ideas, there is always a gift card: the centre itself expects to sell more than 2300 of its own gift cards in the 34 hours at six concierge desks.

He said opening in the early hours of Monday was well worthwhile: more than 10,000 people were expected to be there at 2am including shift workers, restaurant staff who finished work at midnight or even people trying to avoid heavy traffic and crowds.

"It’s a good time to shop," he said.