Daily Covid-19 infections in several Australian states witnessed a big spike on Wednesday as the new BA.2 sub-variant of Omicron is spreading rapidly in the country.

The state of New South Wales (NSW) recorded 30,402 new cases on Wednesday, a big increase from Tuesday’s 10,689. The state also recorded five deaths and 1,016 hospitalisations with 36 people in intensive care, Xinhua news agency reported.

The health authorities said the high number of new cases is partly due to a data processing issue. About 10,000 positive rapid antigen test results registered from Sunday and Monday were included in Wednesday’s numbers, inflating the number reported in the 24 hours to 4 p.m. local time on Tuesday.

Despite the data problem, the health authorities warned the state to brace for a new Covid wave, with cases likely to double by the middle of next month over concerns on the spread of the new variant.

NSW Acting Chief Health Officer Marianne Gale said the BA.2 sub-variant will be “by far the dominant strain” in the state within weeks.

The neighbouring state of Victoria also recorded its highest number of new Covid cases for five weeks, with 9,426 new infections on Wednesday, a sharp increase from 7,460 on Tuesday.

Victoria Health Minister Martin Foley said new daily case numbers were increasing by about 10 per cent on a week-by-week basis.

“In the space of a few weeks we’ve seen the Omicron BA.2 variant go from pretty much nowhere to be seen to the initial reports of at least half of cases,” he said.

The daily infections in South Australia also jumped from Tuesday’s 2,380 to Wednesday’s 3,122, the highest daily cases in almost two months, after 3,777 cases were recorded on January 20.

West Australia recorded 6,062 new cases on Wednesday, the first time for the state’s daily cases to top 6,000.

Adrian Esterman, chair of Biostatistics and Epidemiology in the University of South Australia, told Xinhua on Wednesday that early studies show the Omicron BA.2 sub-variant to be up to 40 per cent more transmissible than its predecessor.

“This brings it close to measles in terms of transmissibility, and measles is the most contagious disease,” he said.

Facing the increasing cases, the Australian Medical Association (AMA) urged the state and federal governments to shore up the health system ahead of the next Covid wave.

“NSW Health Minister Brad Hazzard has already signalled that within six weeks the state could be experiencing double the case numbers we currently have. We’re still learning about the BA.2 sub-variant of Omicron, but it appears to be highly transmissible, and that is concerning,” said AMA President Danielle McMullen.

“Both Delta and Omicron revealed how critical our frontline health workers and health services are, as well as how important it is that they are properly resourced and supported.”

“We need to take the lessons from the previous Covid waves and look at ways to ensure our health system isn’t overloaded again,” she said.