The NSW government expects the Homebush hub, opening on Monday and the first to open in the state, will have the capacity to administer 30,000 COVID-19 jabs per week.

It will be staffed by hundreds of medical personnel and operate six days a week from 8am to 8pm in a specially-fitted commercial building.

For its first two weeks, the hub will be open to people in categories 1a and 1b before expanding to anyone over 50 from May 24.

Victoria has now streaked 25,300 vaccine doses ahead of NSW after bringing six mass vaccination hubs online across the state.

The hub opening comes fresh from the NSW government extending Greater Sydney’s current restrictions for another week, except for mask usage in retail settings.

NSW Health on Sunday said it remains unsure how an infected east Sydney man caught the virus, which shared the same genomic sequencing as a returned traveller from the US in quarantine.

The man, in his 50s, subsequently infected his wife but no other close contacts to date.

Premier Gladys Berejiklian said she was “keen to prevent a super-spreading event” given the “missing link” between the two local cases was yet to be identified.

It means for the next week household gatherings remain capped at 20 people, mask usage remains mandatory on public transport and indoor venues such as theatres and aged care homes, and singing and dancing remains mostly banned.

Hospitality patrons are still not permitted to drink while standing, although retail customers are no longer obliged to wear masks.

NSW recorded zero new locally-acquired COVID-19 cases in the 24 hours to 8pm on Saturday from more than 18,000 tests.

There were an additional six cases in returned travellers in hotel quarantine.