Telstra, Vodafone, Optus and Virgin Mobile are allocating extra stock to their central city stores and advising customers to line up early to avoid disappointment.
They will have stock of the 4.7-inch iPhone 6 and the 5.5-inch iPhone 6 Plus "phablet", but not the Apple Watch, which won't be available until 2015.
Apple has enforced a strict embargo that prevents retailers from displaying the new product or even any boxes bearing the product, much less opening or selling it, until 8 am AEST
Telstra's director of devices, Andrew Volard, said Telstra was "without doubt" anticipating its "biggest iPhone launch on record", claiming "tens of thousands" of customers have registered online for more information about the event.
Mr Volard said it would be one of the biggest sales days of the year for Australia's largest carrier, and he anticipated its stores would remain busy throughout the weekend.
Those queueing at Telstra flagship stores - George Street, Sydney; Bourke Street, Melbourne; Queen Street, Brisbane; and Rundle Mall, Adelaide - are promised prizes, coffee, a DJ and comfy beanbags, and a few seconds of fame on LED screens "connecting" them with fans at other major stores.
Live performances from Australia's Got Talent winners Justice Crew, and the X Factor's Dami Im and Jai Waetford, will take place from 7.40am at the Sydney, Melbourne and Brisbane stores. Justice Crew band members will hand over the first sold iPhones in Sydney.
Fremantle player Aaron Sandilands will be at Telstra's store at Hay Street, Perth from 7.20am (Perth time).
Vodafone, meanwhile, will be serving free coffee at its top five capital city stores, all located near the Telstra stores. These will open from 7am AEST to reduce congestion on footpaths and in malls, the company said, while other stores will open at 8am.
Virgin Mobile will open all stores at 8am AEST, with its five flagships offering "goodie bags" to customers.
All Optus stores, except for two in regional South Australia and Western Australia, will be open from 8am AEST.
Pre-orders for the Apple iPhone 6 opened at 5pm last Friday via the company's official website as well as Australian telcos' websites.
Apple's website crashed in the wake of the demand. Apple said a record 4 million pre-orderswere logged on the first day worldwide.
The supply shortage has spurred hordes of would-be entrepreneurs to spruik their pre-orders on retail site eBay for $1000 more than the official retail price.
More than 200 have posted advertisements on online tasks marketplace Airtasker, offering up to $300 for other people to wait in line for them.
Telcos launched incentives last week such as exit-fee refunds to encourage customers to switch providers when buying the new handsets.
Queues had already begun to appear outside Apple's George Street store last week.
The biggest line, at around 100 or so at the time of writing, was outside Apple's Rundle Mall store in Adelaide.
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