Woolworths Group Ltd and Coles Group Ltd, which together account for two-thirds of Australian grocery sales, said they were once again limiting purchases of toilet paper and paper towels to one or two packs per person after photos circulated on social media showing empty shelves in stores.

The buying restrictions - and images of stripped shelves - are a reminder of Australia's initial response to the arrival of COVID-19 when shoppers stockpiled household goods in anticipation of a protracted shutdown.

With only 7,500 cases in total and 104 deaths, Australia has been easing restrictions on movement, but a string of double-digit increases in cases in the second-most populous state, Victoria, led to a pause in the reopening there - and prompted shoppers to hoard.

Now the pattern has spread nationwide.

"We've regrettably started to see elevated demand for toilet roll move outside Victoria in the past 24 hours," said Woolworths managing director of supermarkets, Claire Peters, in a statement.

"While the demand is not at the same level as Victoria, we're taking preventative action now to get ahead of any excessive buying this weekend," she added.

The company had ordered an extra 650,000 additional packs of toilet paper, 30% over its usual amount.

A Coles spokesman said the chain was restricting toilet paper and paper towel purchases to one pack per person nationwide, with Victoria-only limits on purchase of hand sanitizer, pasta, eggs, rice and other staples.

Despite the Victoria spike, the prime minister and chief medical officer have said the virus remains under control in Australia and the country will continue with a plan to reopen the economy.