One of the country's biggest food charities says it is facing unprecedented demand, as the cost of groceries continues to rise. 

Food rescue organisation OzHarvest has been sourcing food that would otherwise be dumped for more than a decade, due to minor blemishes or a near best-before-date, across the nation.

Today the organisation clocked up its 50 millionth donated meal from supermarket giant Woolworths, which was delivered to St Margaret's Young Women's Shelter in Cairns.

OzHarvest Cairns spokesman Conor Neill said the organisation had been rescuing about 180 tonnes of food every week from 3,000 food donors, including supermarkets, restaurants, cafes and food outlets, and it was hard to keep up with the demand.

"Everyone from school kids to women who are in domestic violence shelters, it's a broad spectrum of people we are delivering to," Mr Neill said.

Experts say grocery prices have risen at their most rapid rate in a decade, with coffee up 47 per cent, olive oil up 30-50 per cent and dried pasta up 30 per cent since the COVID-19 pandemic began.

Domestic and international supply chain pressures and widespread flooding in Queensland and New South Wales have also contributed to pantry woes. 

Donations teaching life-skills 

St Margaret's Young Women's Shelter in Cairns runs a homeless service for women aged 16 to 25. 

House program manager Dearne Lang said they relied on the food rescue organisation to not only feed their clients, which number six young women at any one time, but also to teach them how to cook. 

"A lot of our girls have been couch-surfing or come from environments where skills like cooking and running a household haven't been instilled," Mr Lang said.

Ms Lang said their weekly donation from OzHarvest added up to five meals at night, as well as lunches and breakfasts.

"It's probably around 100 meals a week and that includes all snacks," Ms Lang said.

"We get amazing meat products and vegetables, cereals and milk as well as sanitary items and washing powders."

Whitney, whose last name has been withheld for privacy reasons, said she had been going through family problems at home and had turned to St Margaret's for help.

The 18-year-old said she was starting a certificate two in hospitality on Monday and her time at the home had been life-changing, particularly the fridge that was "never empty".

"We get the box, pack it away and plan a menu," Whitney said.

Mr Neill said it was a thrill to deliver the 50 millionth meal to the women's centre.

"That equates to about 18,000 tonnes of food that has been redirected from landfill, so it's also helping the environment," he said.

"It's a win-win and to get to see the smiles on people's faces when you make that delivery, being appreciated, it's pretty sensational."