Chaos in Adelaide as health chiefs reveal coronavirus infected couple who flew into the city DIDN'T catch the disease abroad but in Australian hotel quarantine – as dozens of staff are plunged into isolation

Two infected returned travellers caught coronavirus in hotel quarantine in Adelaide and not overseas as first thought, health officials have revealed.

An urgent investigation is now underway after genomics testing linked the man aged in his 20s and his wife in her 20s to the Parafield cluster, where the number of cases has now grown to 29.

The couple were previously identified as 'overseas' acquired infections after they returned from overseas on November 11.

Further testing has revealed the pair became infected while in quarantine at the Peppers Waymouth medi-hotel with the same strain of the virus linked to the Parafield cluster in Adelaide's northern suburbs.

Adelaide's Peppers Waymouth is under more scrutiny after it was revealed two returned travellers became infected while in quarantine at the medi-hotel

There are now fears the virus has continued to spread throughout the Peppers Waymouth, which was at the centre of the outbreak that sparked a three day statewide lockdown last week.

Urgent retesting of all staff and guests at the medi-hotel is now underway as a precaution.

'There is no additional risk to the public as the cases are linked to a medi-hotel staff member who has previously tested positive for COVID-19 and contact tracing has already been undertaken,' a SA Health statement read. 

'As a precaution, we are undertaking additional testing at one of our medi-hotels for all staff and guests today.'

Public officials insists there is no additional risk to the public, despite the latest development. Pictured are healthcare workers at a drive-through testing clinic in Adelaide

The fresh outbreak twist forced the state's Chief Public Health Officer Nicola Spurrier to hold a second media conference within hours, where she described the virus strain as sneaky.

'I knew that Covid-19 was highly transmissible, it is more highly transmissible than I first thought,' she told reporters.

'We can have the best PPE and systems set up but you can still transmit this virus.'

'I don't believe anyone has been in the wrong room at the wrong time.'

Professor Spurrier was in a more positive mood hours earlier.

'We're not out of the woods yet but as I said yesterday, I'm confident that we have got rid of this again in our state,' she said on Tuesday morning.

There are now fears the virus has continued to spread throughout the medi-hotel. Pictured are masked locals out and about in the Adelaide CBD

'I haven't popped the cork on the champagne bottle yet, but the champagne is on ice.

'I'd like to see how we go this week. 

South Australia recorded one new case on Tuesday of a man in his 20s who is a close contact of a previously confirmed case. He remains in a medi-hotel.

South Australia's Chief Public Health Officer Nicola Spurrier fronted the media twice on Tuesday following the latest developments in the outbreak