Woolworths chief executive Brad Banducci has announced his looming retirement, as the Australian supermarket giant faces ongoing allegations of price gouging and unfair practices with suppliers.

His exit was announced on the Australian share market on Wednesday morning, at the same time as the company posted its half-year results.

The results showed a $781 million loss, but that was driven by one-off accounting write-downs and, excluding those, the company posted a 2.5 per cent rise in underlying profits.

Food sales rising by more than 5 per cent and profit margins on Australian groceries increased by 0.24 of a percentage point.

That may not sound like much, but those price increases in excess of rising costs equate to more than $60 million of extra profits on sales of just under $26 billion from this division.

Former ACCC chair Allan Fels described the company's write-offs as potentially "camouflage" and "a bit of cover-up" for rising profit margins.

Just weeks ago, Mr Fels released a scathing report on price gouging for the Australian union movement's peak body, which included criticism of Woolworths and its main supermarket rival Coles. 

On Wednesday the ACTU reiterated calls for measures to tackle rising prices, such as a prices commission independent of the ACCC. 

'I haven't managed to dodge every bullet': Banducci

Mr Banducci's retirement announcement comes just days after ABC's Four Corners aired footage of the departing CEO walking out of an interview, as part of its documentary on allegations of price gouging by the major supermarkets, Woolworths and its rival Coles.

Woolworths also came under fire last month for announcing that it would stop selling merchandise specifically for Australia Day in its supermarkets and its associated retail chain Big W.

At its investor briefing on Wednesday morning, Woolworths chair Scott Perkins said the company had been actively looking for Mr Banducci's successor since mid-2023 and that it had always been planning to announce his retirement on Wednesday.

However, Mr Banducci told the same briefing that he had considered deferring the announcement "given recent events".

"It did occur to me to delay but actually that wouldn't have been authentic," Mr Banducci said.

"I tell you, I haven't managed to dodge every bullet. I do believe in the circle of life."

Mr Banducci will retire in September, after almost nine years in the top job.

"I would like to thank Brad for his outstanding leadership and contribution," Mr Perkins said in a statement to the Australian share market.

The supermarket giant announced that it is promoting Amanda Bardwell to the top job, after an "extensive international search process" and interviewing several global retail candidates.

Ms Bardwell has worked for the company for 23 years and is currently heading up its online grocery, e-commerce and loyalty sub-division, WooliesX, which was a key driver of the company's underlying profit growth.

"The board is thrilled with Amanda's forthcoming appointment," Mr Perkins added.

Mr Banducci is still expected to front a Senate inquiry into food prices next month.

"(Mr Banducci) was very successful in business terms, in getting their profits up at consumer expense," Mr Fels told ABC News.

"And that makes him unpresentable at all the forthcoming public inquiries.

Woolworths half-year profit up 2.5 per cent

Mr Banducci's announcement comes on the same day that Woolworths Group released its profit results.

As well as supermarkets, the Group also owns Big W.

The group's overall results show a massive loss of $781 million.

That was after the company booked a $NZ1.6 billion ($1.5 billion) writedown in the value of its New Zealand grocery business Foodland, which it acquired almost a decade ago.

It also booked a $209 million reduction in the value of a stake in ASX-listed alcohol and hotels spin-off Endeavour, which owns bottle shop chains BWS and Dan Murphy's.

But excluding those one-offs, Woolworths announced a 2.5 per cent rise in half-year profit to $929 million.