The mystery fault that saw a Powerball machine fail to spit out the winning ball in a live TV draw has been identified - but Lotto won't say what the problem was.
Lotto is working with Ryo Catteau, the French manufacturer of the $40,000 Powerball machine, to fix the fault, which happened during the October 25 draw.
Failure to perform is rare for the machines, which are subject to strict scrutiny and testing.
It was just the sixth time in the 27 years that Lotto has been running here that the draw was not completed live on television.
New Zealand uses two Lotto machines and two machines for Powerball. Named after the flowers stresa and mimosa, the machines are selected randomly on the night of the draw under the scrutiny of Lotto, Audit NZ and Internal Affairs representatives.
Each machine has two sets of balls, which are also randomly selected and subject to a strict, supervised washing and weighing routine once they have been used in 10 draws.
Lotto spokeswoman Emilia Mazur did not provide details of the fault but said the failed Mimosa machine was tested before the draw and was working perfectly.
The draw was completed off air under the eye of Audit New Zealand scrutineers.
There were no winners and the machine, which is five years old, was taken out of use immediately.
The Stresa Lotto machines are worth $110,000 and the Mimosa Powerball machines are worth $40,000.
Some of the machines used in lotteries overseas have been operating for more than 15 years.
Last night's Lotto draw was number 1431 - it went perfectly, but nobody won Powerball. One Christchurch ticket won a first division prize of $2 million.