There are concerns using vaping as a tool to quit smoking contradicts the rest of the world.

Health New Zealand's free vape programme has given out more than seven thousand devices to smokers, despite Newstalk ZB revealing last year's trial had a success rate of less than half.

Now, a half-million-dollar contract has been signed to provide the devices through New Zealand-owned company, Alt.

Auckland University vaping researcher Kelly Burrowes told Mike Hosking it isn't recommended as a quitting tool, due to the risk associated.

She says that's why other countries aren't doing this.

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