The annual Black Friday shopping frenzy is back.

A decades-old tradition celebrated every year the day after Thanksgiving, Black Friday marks the unofficial start of the Christmas shopping season in America.

Together with its more recent online counterpart Cyber Monday, the sales have become a major global event over the past few years as online shopping has brought the bargains to the rest of the world.

Australian retailers are increasingly getting on board, offering their own deals in a bid to stop some of those dollary-doos going overseas.

"Black Friday and Cyber Monday are the last big sales before Christmas, so it's the perfect time to start your shopping - and bag a bargain while you're at it," said Finder.com.au money expert Bessie Hassan.

"With Australians tipped to spend more than $1300 each on Christmas, a discount here and there could make a huge difference."

Black Friday 2017 brought in $US5.03 billion ($6.87 billion), an increase of 16.9 per cent on the previous year, while Cyber Monday sales were up 16.8 per cent to a record $US6.59 billion ($9 billion), according to Adobe Analytics.

The combined $US11.62 billion ($15.87 billion) paled in comparison to Alibaba's Singles Day event, which last week shattered records with $42 billion in purchases in 24 hours.

Aussie shoppers generally prefer Black Friday, however, spending an estimated $200 million last year. Finder.com.au predicts that figure will top $320 million this year, with research suggesting four million Australians plan to take part.

A survey by ING found 70 per cent of Australians have bought something online from an international retailer in the past 12 months, spending some $6.6 billion at an average of 5.6 purchases totalling $492.77 per person.

While the sale technically starts at 4pm AEDT on Friday, or midnight US time, many retailers now offer deals all week. If the overseas retailer doesn't ship to Australia, you can sign up for Australia Post's ShopMate parcel forwarding service.

"Some brands will even start their sale before Friday, so keep an eye out on your favourite stores," Ms Hassan said. "If you haven't already, sign up for their e-newsletter and follow their social media channels to be the first in the know when the sales hit."

Meanwhile, PayPal head of consumer marketing Liz Lefort has offered some tips for Australians to stay safe and get the most out of the online sales.

Ms Lefort said shoppers should "look for the lock" icon next the website URL indicating the site has security features in place, while avoiding doing shopping while using public Wi-Fi.

Watch out for suspicious links in marketing emails that seem too good to be true, and do your research by looking up reviews for online vendors before purchasing anything.

She also recommends using a price comparison tool. "Use online tools such as Google Shopping, PriceGrabber, NexTag or Pronto to help you quickly determine if you're getting the best deal before you hit purchase," she said.

LATEST BLACK FRIDAY DEALS

Walmart: 33 per cent off Xbox One S 1TB Minecraft Bundle

Home Depot: Up to 40 per cent off power tools and accessories

Amazon: 53 per cent off Ecovacs robot vacuum cleaner

eBay: 60 per cent off Bose TV sound bar

Walgreens: 50 per cent off beauty gift sets

Lowe's: Up to 35 per cent off smart home products

Best Buy: 25 per cent off iPad Mini 4 128GB

Macy's: $25.95 shipping to Australia for orders over $130

Rite Aid: 30 per cent off online, code BLACKFRIDAY

Kohl's: 30 per cent off Under Armour products

Meijer: 36 per cent off Keurig coffee machines

Nordstrom: Up to 40 per cent off, international shipping

Sears: Up to 50 per cent off winter clothing

GAP: 40 per cent off everything, code GIFT

BJ's Wholesale Club: 30 per cent off PlayStation 4 Bundle

JCPenney: 72 per cent off Xersion puffy jackets

Bed Bath & Beyond: 35 per cent off all Nespresso machines

QVC: $US10 off first order, code TEN4U

Victoria's Secret: 15 per cent off total order, code VSSAVE15

Dick's Sporting Goods: 20 per cent off total order, exclusions apply

Staples: 40 per cent off HP Pavilion Intel Core i7 laptops

Bass Pro: Up to 50 per cent off fishing supplies

Tractor Supply Co: Up to 40 per cent off dog beds and accessories

Burlington Coat Factory: Up to 44 per cent off pyjamas

Ulta Beauty: Free nine-piece gift with any purchase over $US60

ASOS: Students get 20 per cent off

Book Depository: Up to 60 per cent off, free shipping

Target: 50 per cent off Hatchimals Surprise

Banana Republic: 40 per cent off purchase, some exclusions

Urban Outfitters: Up to 70 per cent off bedding

Indochino: Up to 70 per cent off everything