Some 42,000 rapid, at-home COVID-19 tests worth more than $500,000 have been stolen from a depot in Sydney, amid a nationwide shortage.

NSW Police were called after man walked in to the freight depot in Mascot on Tuesday afternoon and “took possession” of the tests.

“The incident was reported to police and inquiries are continuing,” a police spokesperson said.

Premier Dominic Perrottet described the theft as “disgraceful”.

“The police will catch you, and at a time when everyone across our state has made incredible efforts in keeping people safe, in making sacrifices, what a disgraceful act,” he said on Wednesday.

It came as Australia continues to grapple with a shortage of rapid antigen tests and price gouging the consumer watchdog has called “beyond outrageous”.

ACCC boss Rod Sims said the agency had received reports of RATs costing up to $500 for two tests through online marketplaces, and more than $70 per test through convenience stores, service stations and independent supermarkets.

Despite wholesale RAT costs being a maximum of $11.45 a test, the agency said prices for the kits were often retailing between $20-$30 and for much more at smaller outlets.

-with AAP