The Australian city of Brisbane will enter another snap three-day lockdown to contain a coronavirus outbreak which has grown to seven cases.

The Queensland state capital - home to over two million residents - will begin the lockdown at 17:00 Monday local time (06:00 GMT).

In January, the city also shut down for three days due to a single case.

The city has seen very few locally acquired cases since Australia's first wave of the virus a year ago.

The Brisbane outbreak, first reported on Saturday, marks the first cluster of community transmissions in Australia in almost a month.

Health officials are yet to determine how the virus leaked into the community, but say it is potentially linked to a hospital doctor who was infectious two weeks ago.

After the lockdown was announced, locals rushed to shops to stock up on goods despite officials urging this was unnecessary.

Video online also showed plane passengers in Sydney scrambling to disembark a flight bound for Brisbane after learning of the announcement.

Queensland Premier Annastacia Palaszczuk said the discovery of four more local cases, reported on Monday, showed there was "more community transmission" in the city.

A lockdown was necessary to help contact tracers contain the spread, she said.

"I know it is really tough. We have Easter coming up, we have school holidays coming up," she said at a press conference on Monday.

"But let's do it now and let's do it right and let's see if we can come through it at the other end."

The lockdown will affect the Greater Brisbane area, which includes the councils of Brisbane, Logan, Moreton Bay, Ipswich and Redlands.

As with previous lockdowns, people will only be able to leave their homes for four essential reasons: exercise, shopping, necessary work and caregiving.

Schools and workplaces will be closed as well as non-essential businesses and services.

Elsewhere across Queensland, residents will have to wear face masks again in shops and on public transport, and home gatherings will be limited to 30 people.

Ms Palaszczuk said: "This is essential everyone that we do this to stop further transmission. We've seen what's happened in other countries. I don't want to see that happen to Queensland."

The popular tourist town of Byron Bay, south of Brisbane, has also been placed on high alert after two infected people visited on the weekend.

Pattern of snap lockdowns

Australia has reported 909 deaths and about 29,200 cases since the pandemic began - a number far lower than many nations. It's in the early stages of its vaccine rollout.

The nation has faced sporadic outbreaks over the past year, with the most severe in Melbourne last July triggering a punishing lockdown that lasted almost four months.

Since then, authorities have acted fast at the start of outbreaks to curtail them early on. Several cities have experienced snap lockdowns in recent months:

Lockdowns have proved to be an effective health measure but the unpredictable shutdowns of cities have left a significant economic toll, experts say.

Australia's domestic tourism industry has been particularly hit hard, with states often shutting their borders to people from declared hotspots.

Interstate travel to and from Brisbane will now be restricted until it's no longer listed as a virus hotspot.