In the first three months Aldi has hit back competitively by investing $75 million (annualised) in discounting its grocery and fresh food range. "Our customers are paying less today than a year ago," Daunt said.

"Price has become a noisy subject (among supermarket operators). The market is definitely competitive. That said we haven't changed fundamentally what we are doing ... as we grow we benefit more and more from scale."

Aldi will begin its "Good Different" multi-media brand campaign this week.

Despite concerns that the entry of Amazon in Australia over the next couple of years will hit most retailers, including supermarkets, Daunt says: "We think the value business model we have stands up well whether you want to hold that up against full line supermarkets here or online supermarkets like Amazon or any potential discounters that may enter the market."

The traditionally secretive Aldi has come out publicly declaring it is sitting on a near 10 per cent share of the national market and has taken 0.6 per cent market share in the first quarter of 2017, compared with the same quarter last year.

It has reached gross revenue of $7.5 billion in 2016 - the equivalent of a 12 per cent increase on the previous year.

While much of the market share gain will have come from new store openings in South Australia and Western Australia, Daunt said the eastern states were still experiencing growth.

While Daunt confesses this does not sound like a lot compared with the hundreds of millions Woolworths and Coles have boasted to have ploughed back into lower prices, he says that given the size of Aldi against Coles and Woolworths, its discounts are significant.

He also disagrees with retail analysts' reports over the past six months that argue Aldi's sales growth rate is under pressure in its mature market as new stores cannibalise sales from established stores.

Daunt says Aldi's expansion west has been successful and it now holds a 4 per cent market share in South Australia and about 3 per cent in Western Australia.

Meanwhile, Aldi won't concede that Amazon will hit the grocery market hard. Daunt says that "traditionally in grocery consumers have proven difficult to convert to online because all of us like to choose our own banana, our own tomato and steak because there is a high degree of variability ... but if and when they will get into that space our strategy is about the noise around pricing, is just to stick to our knitting".

But he contends that in the non-food retail sector Amazon is a real threat.

"We expect them to be very successful in the non-food space and definitely have an impact on non-food retailers in Australia."