A passenger from Papua New Guinea who was accidentally allowed into the green zone at Brisbane Airport for two hours has tested positive for coronavirus.

A man who was accidentally ushered from the quarantine red zone into the green zone at Brisbane Airport has tested positive for coronavirus.

The man and his companion were inadvertently directed into the green zone while transiting through Brisbane after arriving on a flight from Papua New Guinea about 9.45am on Thursday.

The pair were in the same area as another 390 passengers due to depart for New Zealand for just over two hours before the mistake was realised.

An initial test failed to deliver a concrete result before further testing confirmed the man was positive.

His companion tested negative on Thursday night.

Queensland Chief Health Officer Jeannette Young said the international terminal was a "venue of concern" but considered the risk of transmission low given mitigating measures were followed.

"Through CCTV footage we've seen that people were wearing masks, people were maintaining social distance (and) the table that the two people sat at was thoroughly cleaned," she said on Friday.

"We don't have genome sequencing yet on this man, and we may not get that because the amount of virus was so low, which is a good thing."

Anyone who was in the terminal between 9.45am and midday on Thursday is advised to monitor their symptoms and get tested immediately if they feel unwell.

The infected man was in the same area as passengers due to fly on Air New Zealand NZ202 from Brisbane to Christchurch, Air New Zealand NZ146 from Brisbane to Auckland, and Qantas QF135 from Brisbane to Christchurch.

Dr Young said some airport staff were in quarantine but did not expect there to be broader consequences for Queensland as a result of the breach.

The NZ health ministry has also been notified about the man's positive test.

"We are in contact with Queensland Health officials today following this reported breach and will be able to provide updated information as soon as we can," it said on Friday.

NZ Prime Minister Jacinda Ardern said "a lot of work" went into travel arrangements between the two countries, and understood the risk to other travellers was considered relatively low.

"From time to time, we are going to have to manage situations where there may be lapses," she said on Friday.

Brisbane Airport Corporation said the breach was due to "human error".

The pair had visited two retail outlets and used the bathrooms in the green zone.

BAC said those areas had been cleaned thoroughly and all green zone staff were wearing personal protective equipment at the time.

Three green flights departed during those two hours, but airport officials said only "a handful" of passengers were in the vicinity of the couple.

"BAC is conducting a thorough investigation and unreservedly apologises for this human error," the operator said on Friday.