A widespread IT outage is affecting around 30 Woolworths supermarkets across the country, preventing customers from making purchases.

The majority of stores hit by the outage are Woolworths Metro stores, a Woolworths spokesperson has advised.

"We are working to resolve the issue as quickly as possible," the spokesperson said.

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"There are no issues with the Woolworths website.

"We apologise to our customers in those impacted stores for the inconvenience and thank them for their patience as we work through this IT issue."

Woolworths has more than 1100 stores across the country.

More to come.