Authorities in New Zealand are trying to track down sweets containing a potentially lethal dose of methamphetamine that were unwittingly handed out by a homeless charity.

The Auckland City Mission charity distributed care packages containing the sweets after they were donated by a member of the public.

It is now attempting to contact 400 people who were potentially handed the packages.

Three people were taken to hospital after consuming solid blocks of the drug wrapped in sweet wrappers, authorities said. They were later discharged.

Meanwhile, Auckland City Missioner Helen Robinson said eight families - including at least one child - had reported consuming the contaminated sweets, however, she said the "revolting" taste meant most spat them out.

Handout image released by the New Zealand Drug Foundation showing the sweets that have been laced with meth amphetamine. Image: New Zealand Drug Foundation

Methamphetamine is a highly addictive stimulant that affects the central nervous system.

The New Zealand Drug Foundation said the amount of the drug in each sweet is up to 300 times the level someone would normally take and could be lethal.

"Funny Tasting

The charity was alerted by a food bank client who reported a "funny tasting" sweet.

The wrappers had the label of Malaysian brand Rinda, while the sweets were said to be pineapple flavour.

Staff tested them and called the authorities. One staffer was taken to hospital.

Smuggling

Ben Birks Ang, a spokesperson with the New Zealand Drug Foundation, said disguising drugs as regular products was a common cross-border smuggling tactic.

Each sweet has a street value of £473, he added, suggesting the donation to the charity was accidental rather than anything more sinister.

Detective Inspector Glenn Baldwin said "initial perceptions" were that it was an importation scheme gone wrong.

He said 16 sweets have been recovered, however, it remains unclear how many are still out there.

Reporting from IRN and Michael Staines.