Queensland Premier Annastacia Palaszczuk says concerts and large parties will be banned, with limits on gatherings at beaches and apartment complexes.

"This is a mass event. It poses a high risk," she told reporters on Friday.

She says such events will not only put the students who attend at risk but also the people they contact during and after, such as their grandparents.

Ms Palaszczuk acknowledges the struggle Year 12 students have endured finishing their studies with schools closing then reopening.

"We've had to make these decisions because it is about the health of everyone," she said.

"It's a tough year for everyone. And, hopefully, things will get better by the end of next year and we can have a double celebration."

Three people in their 30s were diagnosed with COVID-19 in Queensland overnight, bringing the number of active cases to 20.

All are linked to the corrections training centre at Wacol, in Brisbane's southwest, where a senior trainer was diagnosed with the virus on Thursday.

Two of the infected people - a 33-year-old woman and a 37-year-old man - are corrective services recruits and contracted the virus in a dining room at the academy.

They live at Pimpama and are the first confirmed cases of community transmission on the Gold Coast.

The other is a 33-year-old man who attended a training course.

He lives in Forest Lake, where the senior trainer also lives.

Chief Health Officer Jeannette Young said health officials did not know how the virus had spread within that training centre or who was the primary case.

"I'm pretty sure they got it in the centre but ... they've been out in the community," Dr Young said of the pair from Pimpama, who carpool together.

"So there is a real risk they've spread it in the Gold Coast."

Health restrictions limiting the number of people who can gather - where a COVID-19 safe plan is not in place - to a maximum of 10 will be extended to the Gold Coast from 8am on Saturday.

Personal protective equipment requirements for hospitals, aged care facilities and disability service providers will also be extended to the region.

The same restrictions currently apply to Brisbane, Ipswich and Logan.

It comes as thousands of prisoners potentially exposed to COVID-19 remain locked down in their cells.

About 7000 inmates from the central coast to the southeast of the state were quarantined after the trainer was diagnosed with the virus.

The 60-year-old man didn't work in a prison but trained 14 prison officer recruits and came into contact with 11 other staff in the days before he was diagnosed.

The 25 staff have since been tested for COVID-19 and returned negative results.

A second group of 19 recruits was also tested along with the two Pimpama residents found to be infected.

The lockdown limits movement in and out of correctional facilities with prisoners confined to their cells and personal or professional visits banned. Staff who interact with them will wear protective clothing.

The restrictions will remain until revoked by Dr Young.

Australian Associated Press