Police say 16 meth 'lollies' have been recovered so far but they are unclear how many are still out there.

Operation Tirade has been launched after the discovery of blocks of methamphetamine disguised as Rinda-brand pineapple lollies in parcels handed out by the Auckland City Mission.

Detective Inspector Glenn Baldwin says police are treating the issue with urgency and wanting to make sure rest of the lollies are handed in as quickly as possible to minimise harm.

"That is the priority at this stage of the investigation."

If people felt it was difficult to contact police, Glenn asks them to get in contact with a hospital, doctor or medical professional who can contact police on their behalf.

"This is about safety and getting them out of circulation."

Since Tuesday afternoon police have been contacted by a number of people who have been in possession of the lollies.

One was a pensioner in Auckland CBD who came forward after tasting it.

"I'm aware of a further six lollies in Ōtāhuhu this afternoon and police have secured those as well."

Three people have been hospitalised as a result of tasting the lollies including a charity worker, a teenager and a child.

They were all reported to be OK.

The national poison line can be reached at 0800 764 766.

The lollies found to contain methamphetamine. Photo: NZ Drug Foundation.

Forensic testing has been carried out by police on one of the lollies and it was confirmed to be meth.

"Police are treating these lollies as fully contaminated until we can prove otherwise."

Police have not yet checked other items that were in the food parcels but there has been no reports of other food contaminated.

The origin of the drugs was being investigated and it was believed it was imported into the country, Glenn says.

"Drug importation is complex and organised criminal groups use a range of measures and techniques to try and evade enforcement agencies not only in New Zealand but around the world.

"I again want to stress that this is a developing situation."

It may take some time to understand what has happened and how, he says.

Glenn encourages people not to try to on-sell the meth.

"If a child eats one of these they will be in significant danger."

Operation Tirade was in its infancy and eight investigators were working on it supported by 24 hour response teams, Glenn says.

-RNZ