A Daily Mercury reporter at the scene said services had just been restored and customers were once again flowing through the registers.
Others have been told to leave the stores.
Stores temporarily closed in response to the outage.
"Shoppers have been told to leave groceries in baskets in the aisle", one customer wrote on Twitter.
According to multiple reports, Woolworths supermarkets around Australia are experiencing a technical issue that prevents them from processing any transactions.
UPDATE 5.10PM: WOOLWORTHS have responded to customer complaints confirming the national outage this afternoon.
At Haymarket, in Sydney, staff shut the store and were turning people away, telling them to "come back in about an hour". "We apologise for the inconvenience this caused our customers".
Shortly after 4pm, the issue began affecting all registers across the country.
Supermarket giant Woolworths has suffered an IT outage this afternoon which affected registers at its stores nationwide.
Registers have shut down with stores unable to make sales.
The spokeswoman did not say what caused the outage.
News Corp Australia has contacted Woolworths for comment.