Health officials are scrambling to contain a worrying cluster of cases, centred mainly on one family.

Latest figures indicate 17 people from that extended family have either tested positive or are suspected to have the virus.

Another case is a close contact of the family while two further cases have been confirmed among security guards at a quarantine hotel in Adelaide, the initial site of the outbreak.

The SA situation comes amid ongoing improvement in Victoria, Australia’s worst-hit state, and NSW. It also complicates Queensland’s move to further ease restrictions on social gatherings this afternoon.

It’s now believed a cleaner at the hotel picked up coronavirus from a surface, despite not coming into direct contact with any returned traveller with a confirmed case.

On Monday, people queued at testing stations across Adelaide for more than five hours with some being turned away.

Some centres stayed open late and SA Pathology boss Tom Dodd said that would continue.

On Tuesday, queues were even longer, with people lining up at drive-through centres from 4 am.

“Clearly, we need to have all those sites operating for longer hours going forward from today,” Dr Dodd told ABC radio.

“I apologise to anyone who queued for a long time and wasn’t able to get a test. We don’t want to have that happening.

“We need to ensure we stay open to swab all the people who present.”

SA Premier Steven Marshall said he was sure Monday was a record day for testing numbers and praised South Australians for turning out.

The state’s previous highest number of tests in a single day came in on August 7 when 7254 people were checked.

The Premier said with just one new case confirmed overnight, SA was faced with a different situation to that of yesterday when case numbers were rising more rapidly.

“We have gone hard. We’ve gone as quickly as we possibly could. We’re hopeful that we’ve got this in time,” he told Nine’s Today program.

“We’re cautiously optimistic about what might happen today.”

The outbreak has prompted other states to re-impose border restrictions as a precaution. Queensland has told thousands of people who arrived from Adelaide before the cluster news to self-isolate, and ordered more recent arrivals into hotel quarantine or onto flights back to SA.

Five ticket-holders for tomorrow night’s State of Origin rugby league game at Suncorp Stadium – which will be full due to COVID-19 restrictions easing in Queensland from later today – have been contacted and reminded they should not attend.

Queensland Health Minister Yvette D’Ath said the restrictions on people arriving from South Australia were necessary to avoid an outbreak requiring restrictions on five million Queenslanders.

“We have had 64 days without locally-acquired transmission, that’s what we need to maintain,” D’Ath said, after the only new case overnight was a person already in hotel quarantine.

“We cannot afford to be complacent.”

The so-called Parafield cluster has shut down at least four schools in Adelaide and has forced a nursing home into lockdown, with cases confirmed among staff.

A fast-food restaurant has also been shut while warnings have been issued for a range of shops and other venues and public transport services asking people to carefully monitor for symptoms if they attended any of those locations over certain times.

The cluster has prompted the SA government to reimpose a range of coronavirus restrictions.

From Tuesday, all gyms, recreation centres and play cafes are closed for two weeks with community sports fixtures and training cancelled.

Funerals and family gatherings are now capped at 50 people, and all church gatherings at 100 people.

Pubs, clubs and restaurants are limited to 100 people along with all other public gatherings.

All venues must abide by a rule of one person to every four square metres.

Masks are mandatory for workers in personal care businesses and for workers in aged care if physical distancing is not possible.

Aged care workers will be limited to working at just one site but schools will remain open.

The government has asked all people to work from home if they can and to reconsider unnecessary travel of any kind.

Meanwhile, Victoria has gone 18 days, and NSW 10 days, without any cases of community transmission. If the good health news is able to be sustained, the trend will likely prompt Queensland to further ease border restrictions on November 30.

-AAP