The dollar figure was determined in the latest supermarket price survey from consumer group Choice, which compared the average cost of a basket of 33 items at Aldi, Coles, Woolworths and IGA.

Each basket included 28 packaged products and five fresh fruit and vegetable items, including beef mince, eggs, chicken breast, apples, broccoli and potatoes.

Conducted by undercover shoppers in 110 Australian supermarkets in March, the survey found the German discounter offered the cheapest basket of budget brand groceries, at $91.76.

This was compared with budget baskets at Coles ($99.40) and Woolworths ($97.31).

Choice found the most expensive basket of leading brand goods at IGA, which was 6-7 per cent more expensive than the same basket at Coles ($170.54), and Woolworths ($168.74).

For a basket of comparable products at the three supermarkets, Aldi charged $102.50, Woolworths $112.89 and Coles $113.10.

Choice did not release a list of the product combinations in any basket.

"Although the big supermarkets make a lot of very loud claims about value, it's clear Aldi is Australia's cheapest supermarket and it is forcing the big two to compete on price," said Choice spokesman Tom Godfrey.

While it was the most competitive on price, Mr Godfrey said Aldi's offering lagged behind Coles and Woolworths when it came to "stocking leading brand items and products with some Australian ingredients."

Of the 28 packaged items in the baskets, Coles contained 22 with "at least some Australian ingredients," Woolworths, 21 and Aldi, 17.

A Woolworths spokeswoman said the supermarket regularly reviewed its range to ensure "the most popular products in-store are also the best value."

As the survey was conducted in March it did not consider recently launched products, such as those in the new Woolworths food range.

"[Our] new food range has been created with nutritionists and chefs and taste-tested by customers to ensure we are providing great quality and healthier options that are also great value," the spokeswoman said.

Around Australia the most expensive grocery baskets could be found in Tasmania, followed by the Northern Territory, while South Australia was revealed to have the cheapest.​

A spokesman for Coles said the Choice survey of 33 items did not provide a full or accurate picture of the 25,000-plus products it offered, nor did it include special discount pricing.

"As part of our commitment to lowering prices, Coles recorded cumulative food and liquor deflation of 7.5 per cent from FY09 to FY16. We are continuing to reduce prices on thousands of branded and private-label products across our stores, so customers can save on their shopping at Coles."

Mr Godfrey said another noticeable trend was the continued rise of 'copycat' and 'phantom' brands.

"Copycat products look similar to leading brand items when it comes to colour and design but there's a big difference in price."

Last year Fairfax Media conducted its own price comparison of groceries at Coles, Woolworths and Aldi.

It found popular branded products such as Coke, Tim Tams and Weet-Bix cost an extra 12 per cent at Woolworths and an extra 14 per cent at Coles, compared with Aldi.

Paul Foley, the ex-Aldi executive who helped Aldi set up in Australia, told Fairfax Media in November that Aldi only stocked branded goods where "the quality available from private-label suppliers is inferior...or the marketing behind that brand is so huge that the consumer demands it, like the cola from Coke."

"Inevitably this means the discount per kilogram or litre on these branded items is nowhere near the discount Aldi offers on private label items," he said.

An Aldi spokeswoman said the store has worked to influence grocery pricing since establishing more than 16 years ago.

"The ACCC's 2008 Grocery Inquiry [found] that major supermarket chains reduce their prices in locations where Aldi is present. We are delighted to see that our entry into South and Western Australia has positively impacted grocery pricing in these states."

- with Madeleine Heffernan