"Deltacron" and another recombinant Covid infection have been detected in Australia.

In its weekly Covid report, NSW Health revealed the state has identified one Deltacron infection, a mix of Delta and Omicron BA.1, and a recombinant infection of Omicron's sub-variants BA.1 and BA.2.

Recombinant viruses are when two virus strains merge to form a new, single, hybrid strain.

While these infections were reported for the first time today, NSW Health said they were not identified this week.

Deltacron was detected for the first time at the Institut Pasteur in Paris in February and has since been found in the US, UK and Denmark.

While the hybrid strain sounds scary, scientists say it was expected and it is too early to tell what impact it could have.

University of NSW virologist Professor William Rawlinson told the Sydney Morning Herald people with recombinants had not shown worse signs so far.

"We need to keep a close eye on the relationship between these cases and severity of disease," he said.

Passengers wearing facemasks arrive into the international arrivals area at Sydney's Kingsford Smith Airport after landing from New Zealand. Photo / Getty Images

Trinity College biochemistry Professor Luke O'Neill wrote for the Conversation in March that more work needed to be done to determine whether Deltacron would be "any better at evading immunity" and causing "more severe disease".

"There are currently too few Deltacron cases to draw any conclusions on these issues," he said.

"What we need are experiments to determine the properties of Deltacron. Scientists have started that process and have been able to infect cells with it, so hopefully we'll have answers in time."

Two new mixed infections were also detected in NSW this week, which occurs when two separate virus sequences are detected at the same time in a specimen.

They were a mix of Omicron BA.1 and BA.2, though neither of the specimens were collected this week.

Seven mixed specimens had already been identified in NSW before this week, three with Delta and Omicron BA.1 and four with Omicron BA.1 and BA.2.

NSW recorded 20,396 new Covid cases today and eight related deaths.