The minister is expecting an update on Wednesday after environmental testing by ESR at the Pullman Hotel.
"We may not ever form a 100 per cent solid opinion of what happened at the Pullman," Hipkins said.
A technical group believes it most likely involved airborne transmission - rather than surfaces - but it was a matter of working out how that happened, Bloomfield said.
An air-conditioning theory is still being pursued but Hipkins said the international evidence was "patchy at best".
It will wait until an investigation into what happened at the Pullman is completed before bringing it back online.
CCTV cameras will be upgraded at the Pullman before guests start returning by the middle of February.
Workers at the Jetpark - the quarantine facility - shouldn't be moonlighting in other jobs. Most were now directly employed by the Government.
There were 3017 tests processed yesterday and all results have been negative - including the close contacts of cases.
Hipkins asked New Zealanders to show some kindness and respect and said it was "never anybody's fault" if they caught Covid-19.
He said there'd been examples of people being vilified for isolating and getting tested.
He thanked workers who'd gone "over and above" to process tests and to the returnees who were being asked to stay in their rooms for longer.
"It's never easy."
Hipkins said it shouldn't depend on "who you know" as to whether a MIQ refusal was reviewed.
He encouraged anyone refused compassionate entry to ask for a review and called it an "appeal process".
He said the capacity for MIQ was about 4500 and the Government wasn't looking to set up more facilities.
Hipkins said "it's never helpful" to put the achievement of keeping Covid-19 out of New Zealand as being "down to luck" or minimising the hard work of border workers.
The total number of active cases in managed isolation is 69.
The Orewa family who tested positive and moved to a quarantine facility are continuing to recover, said Bloomfield.
There are four testing centres in Auckland. The pop-up testing centre in Albany closed after demand waned.
Bloomfield has asked his team about whether they need to change reporting on historical cases while the international community report acute cases. They are looking at reporting historical cases separately.
Officials are finalising the numbers of how many people are believed to have caught Covid in managed isolation facilities.
Bloomfield said in-facility transmission would be reported.
He repeated Hipkins' message to be kind and said "we're all in this together".
Hipkins said the situation in Perth didn't necessarily change anything from a week ago as they always knew there could be small outbreaks.
"It is an illustration about why we've been cautious."
Hipkins said he'd endorse the "go hard, go early" message which had served New Zealand so well.
The ministerial advisory group on vaccines will meet tomorrow and once it's reached a recommendation that's made to Medsafe - then it will be up to the Government, Bloomfield said.
There were no new cases in the community at the weekend.
Changes at the Pullman Hotel also took effect, including:
• After having have had their day 11/12 test, people will be required to stay in their rooms until they get a negative test result and are advised they can depart from the facility.
• Returnees departing from the Pullman will be required to have a day 5 post-departure test and stay at home until a negative test result is returned.
• If they become symptomatic following their departure from the Pullman they need to self-isolate and get a test.
• Returnees are required to wear a mask when departing from the facility or going for their day 5 test.
