Australia's second most populous state Victoria on Sunday reported two new locally acquired Covid-19 cases, with the low number raising hopes that a hard lockdown in the state's capital Melbourne will be eased on June 10.
Two other new cases were reported on Sunday by an aged care home, but the state had yet to confirm them.
The four new local infections bring Victoria's total cases to 74, including two recovered cases, in the outbreak that began in late May after a man who tested negative in hotel quarantine in Adelaide returned to Melbourne and tested positive.
The daily rise was down from five new cases reported on Saturday. All four new cases were linked to existing clusters.
Officials said that Melbourne's restrictions would probably be eased on Thursday.
"If we can, we will lift it early, but at this stage our expectation is that it will continue to Thursday," Victoria's deputy chief health officer Allen Cheng told reporters.
Health authorities remain worried about the emergence of the highly infectious Delta variant, which has now extended to 10 cases, as the source has yet to be identified and there has been no genomic match so far with any other cases in Australia.
The Delta variant, which has been classified by the World Health Organisation (WHO) as among the four Covid-19 variants of concern due to evidence that it spreads more easily, likely caused the latest devastating outbreak in India.
"The last thing we want to see is this variant of the virus getting out and becoming uncontrollable," state deputy premier James Merlino said.
A family that travelled to a beach town in New South Wales state were the first in Melbourne to be infected by the Delta variant.
"We are concerned about who it was who might have given them the infection and therefore could there be other infections related to that," Cheng said.
Arcare said it had two new cases at one of its aged care facilities. One of the new cases was a nurse and the other a resident who lives close to two residents infected earlier.
Australia has been relatively successful in controlling the virus with snap lockdowns, tight border restrictions and social distancing, but has had a slow vaccine rollout.
Australian Health Minister Greg Hunt said on Sunday that Canberra would deliver an extra 100,000 Pfizer (PFE.N) vaccines to Victoria over three weeks from June 14 and would double the number of AstraZeneca (AZN.L) vaccines to 230,000 for medical clinics in the state.
Victoria has accounted for two-thirds of the more than 30,100 Covid-19 cases and 90% of the 910 deaths in the country since the pandemic began last year.
Merlino on Sunday announced A$32 million ($25 million) in assistance to regional tourism and accommodation operators to make up for a disrupted ski season, adding to A$460 million committed last week to businesses affected by the lockdown.