9 new cases and a missing link: Everything we know about Queensland's growing outbreak.

Queensland has woken to the first day of their three-day lockdown, as the state recorded nine new locally acquired cases of COVID-19 overnight, in addition to the six cases recorded yesterday.

This is the highest number of local cases for Queensland in the past 12 months. All new cases are confirmed to be of the Delta strain.

There are 11 local government areas in southeast Queensland who have been plunged into the snap lockdown. The LGAs are: Brisbane, Ipswich, Logan City, Moreton Bay, Redlands, Sunshine Coast, Gold Coast, Noosa, Somerset, Lockyer Valley and Scenic Rim.

Here's what you need to know about the snap lockdown. 

How did the Queensland outbreak start?

Doctor Jeannette Young says there is still no known link between the new positive cases and the origin of the infection. Image: Getty.

The index case of this outbreak is a 17-year-old high school student from Brisbane's inner-west who tested positive on Thursday.

The student's two parents and two siblings have also tested positive, as well as a medical student who tutors the girl. A staff member of lronside State School, which the family's youngest child attends, has also tested positive.

However, this is still no known link between these positive cases and the origin.

Queensland's Chief Health Officer Dr Jeannette Young said genome sequencing has linked the high school student's infection to two people who are in hotel quarantine after returning from overseas. But they don't know how COVID-19 transmitted between them.

"I don't know where this virus is at the moment," Dr Young told reporters on Sunday morning. "Please come forward [for testing]. Because then we will be able to find those other chains of transmission which I expect are out there."

Dr Young is particularly concerned about Sunshine Coast, saying she believes there are unknown cases in the community. 

"In the Sunshine Coast, please, it is particularly important that you come forward because I suspect that is where this outbreak started, and then has reached a critical level where it has started to escalate and we had picked [it] up at the escalation point."

What are the Queensland lockdown rules?

Exercising is one of the four essential reasons residents can leave their home. Image: Getty. 

Residents in the affected lockdown areas can only leave home for essential work, study or child care, to exercise, buy food and supplies, and to receive healthcare, including being tested for COVID-19 or vaccinated against it.

Any non-essential travel must be within 10km from home and everyone must wear a mask when they are outside their home.

People doing exercise can do so with one person who does not live with them.

Funerals and weddings in the lockdown zone will be limited to 10 people and hospitality will be takeaway only. Cinemas, hairdressers, gyms and places of worship have to close.

All schools in the lockdown zone will be closed on Monday and Tuesday, while all staff and students of Indooroopilly State High School and Ironside State School are in quarantine for two weeks.

Schools will be open on Monday and Tuesday for the children of essential workers and for children who are vulnerable.

The lockdown extends to anyone who was in one of the 11 LGAs as of 1am Saturday, so even if they have since travelled to another part of Queensland they must abide by the restrictions.

Failure to comply with health directions could incur a $1,378 fine, Queensland Police said.

NRL still permitted to play.

NRL has been cleared to continue the competition, despite the lockdown. Image: Getty. 

Despite the lockdown, the NRL has been cleared by Queensland Health to resume play with a triple-header at Suncorp Stadium on Sunday.

Less than 12 hours after being forced to postpone Saturday's three matches due to the lockdown, the NRL was given the green light to continue.

Saturday's games will now go ahead on Sunday, before a double-header at the same ground on Monday night for the games originally scheduled for Sunday.

It comes after the league put forward a plan to Queensland Health to resume, with all players under stringent restrictions.

Players will be tested daily for COVID-19, there will be compulsory masks for all players and officials not playing as well as reduced personnel at games.

Feature image: Getty.