Emergency services have been stood down after white powder at the centre of a callout in central Wellington was declared safe.
Police, ambulance and firefighters, as well as a hazardous materials unit, went to the incident at a block of flats on Boulcott St about 12pm.
Sergeant Daniel Hughes, of Wellington police, said testing by the bomb squad revealed the powder did not pose a chemical or biological threat.
While the substance not yet been identified, a letter with the envelope claimed it was a sample of flour.
Efforts would be made to track down the sender, Hughes said.
Three flatmates found the package in their mailbox last night and later found it contained white powder.
They were unsure what to do, but this morning decided to alert authorities.
The package had been hand delivered, Hughes said.
The flatmate who opened the package was isolated.
"We have to take precautions - it's usually nothing but you don't know if it could be poison, drugs or something else that could cause harm to somebody," Hughes said.
One of the flatmates, Jonty McBrearty said he was sick in bed when he was told to leave.
''Better safe than sorry I suppose,'' he said.
- The Dominion Post