Greater Brisbane will also become a hotspot from 5pm, restricting interstate travel, and schools will close except for children of essential workers. The Easter holidays start on Friday.

Premier Annastacia Palaszczuk said she did not sleep last night but believed a rapid lockdown was justified given the more contagious UK strain was involved.

“I am very worried, I am very concerned,” Palaszczuk told journalists today.

“I apologise for the inconvenience it’s going to cause people but health has to come first here.”

Palaszczuk urged Queenslanders to follow the restrictions, and heed the advice to wear masks in public, but insisted there was no need for panic buying today.

The lockdown has been ordered after the latest cluster grew to seven cases, and is still believed to somehow be linked to the previous mini cluster that also prompted a lockdown. On that occasion, a returned traveller with the UK strain somehow infected another guest in quarantine at the Hotel Grand Chancellor, and then a doctor at the Princess Alexandra Hospital.

Authorities believe a man who was somehow linked to that mini cluster then infected his brother, who lives at Stafford, who subsequently infected his housemate and a friend at Strathpine.

Overnight, it was confirmed two workmates of the Strathpine man were also infected – one had travelled to Gladstone for three days while infectious, before being ordered into quarantine – along with two women, including a PA hospital nurse. The women are sisters and travelled to Byron Bay while infectious, without knowing the risk. It is still not clear how they were infected.

The other six cases were detected in hotel quarantine. Queensland will halve the number of overseas travellers it accepts in an effort to reduce the strain on the system, already under pressure from the Papua New Guinea epidemic.

Chief Health Officer Jeannette Young said the lockdown would buy authorities time to conduct contact tracing.

“We now have significant community transmission and significant numbers of venues that are of concern,” Young said.

Queensland now has 73 active cases of COVID-19. Tests were conducted on 6130 people yesterday, most of them in Greater Brisbane, and Young again implored anyone who is sick to get tested.

From 5pm, residents of Greater Brisbane – Brisbane, Logan, Redlands, Ipswich and Moreton Bay council areas – will be confined to their homes unless they are going out for essential work, medical attention, to buy food, support a vulnerable person or exercise (subject to specific rules). That will also apply to anyone who lives somewhere else but has been in Greater Brisbane since March 25.

Greater Brisbane residents and recent travellers to Brisbane will also have to wear masks unless they are by themselves in a room or in their own home, and can only have up to two visitors to a home.

“For the rest of the state, outside the five local government areas that make up greater Brisbane, I’m asking that you wear a mask when you can’t physically distance, when you’re inside or when you’re on public transport,” Young said.

The Gladstone link has also prompted a limit of 30 people for household gatherings outside of Greater Brisbane, and a requirement that any dining out or drinking in venues be seated.

Young said visitors would be banned in hospitals, aged care, disability services, and prisons across the state to protect the most vulnerable.

Genome sequencing results are due later tonight to help determine how the two women were infected. The nurse had done some previous shifts in the COVID-19 ward and was on leave when vaccinations started. Young could not be certain that was where she was infected, and said any potential link with the PA Hospital doctor would also be investigated.

The previous biggest Queensland cluster was centred on the Brisbane youth detention centre last year and involved 55 cases.