How late can you leave online shopping before Christmas?

Amazon says most Australians will be able to shop online until Sunday and still receive their orders in time – and has recruited singer Guy Sebastian to surprise some lucky customers.

Amazon is tapping the gig economy as part of its efforts to accept Christmas gift orders up until Sunday, two days later than Australia Post for standard parcels, and has recruited singer Guy Sebastian to surprise customers.

The Seattle-based tech behemoth has engaged a Flex fleet that allows drivers to select a block of hours to work.

Like Australia Post, Amazon has a mix of employees and contractors to deliver parcels, which has allowed it to offer free same-day deliveries for its Prime customers in Sydney and next-day delivery in key regional areas including the Blue Mountains, Canberra, Gold Coast, Sunshine Coast and Victoria’s Mornington Peninsula.

It is the busiest time of the year for logistics companies; last Christmas Australia Post delivered almost 100 million parcels.

Sebastian – who returned to Australia from Amsterdam late on Tuesday night and has bought a few Christmas gifts online – said up until a few weeks ago he did not fully understand how packages were delivered.

Guy Sebastian and members of the Mount Druitt Choir sing to delivery partners at Amazon's delivery station at Eastern Creek in western Sydney.

“I’m a bit of an online shopper and I was wondering how they just get to me so quickly. It was actually through this (Amazon partnership) that I learned that so many of them are everyday Aussies working as Amazon Flex delivery partners,” he said.

The singer joined Flex driver Brendan McEntee in Sydney to deliver parcels on a round, where they surprised customers by singing Christmas carols with the Mount Druitt Choir.

“They (Flex drivers) just work tirelessly, especially as the holiday season hits – they’ve got to ensure the packages get there on time. So being able to spread a little bit of cheer to them and to the customers, it was pretty cool, especially with the choir involved.”

During his youth in Adelaide, Sebastian worked as a delivery driver for Steadfast Logistics, a warehousing and distribution provider.

“They do all these vitamin bottles for like Johnson & Johnson and all these other companies, so I’d unload the whole bunch of vitamin bottles from the containers – I was a forklift driver as well – and stack them all for racking,” Sebastian said.

“And then there were a lot of deliveries, so I was on the road. It was my favourite part of my job, doing those deliveries. I was listening to a lot of books and heaps of music. I love it.”

Pop singer Guy Sebastian and delivery partner Brendan McEntee surprise residents at Eastern Creek and Minchinbury in western Sydney.

Amazon Flex involves people delivering in their own vehicles when it suits them. They can schedule delivery blocks up to a week in advance, knowing the amount they will earn upfront, and are paid weekly.

Amazon expects Prime members in Sydney, Wollongong, Newcastle, Gosford, Melbourne, Bendigo, Ballarat, Geelong, Brisbane, Gold Coast, Sunshine Coast, Toowoomba, Bendigo, Perth, Adelaide and Canberra to be able to shop from a range of eligible items up to Sunday to receive them in time for Christmas, with free delivery.

Australia Post says gifts should be sent by this Friday for most areas in Australia.

It says for last-minute shoppers they can send items up until December 23 if they buy Express Post – but that network doesn’t cover all of the country and people are advised to check eligible postcodes.