Wellington - Michael Swann, 47, was sentenced Wednesday to nine years and six months in prison for New Zealand's biggest-ever fraud by a worker on his employer, news reports said.

Swann was found guilty in December in the Dunedin High Court of embezzling 17 million New Zealand dollars (8.5 million US dollars) over six years while working as chief information officer of the Otago District Health Board.

His friend, Kerry Harford, 48, a surveyor from Queenstown, who allegedly supplied Swann with 198 false invoices during the period, was jailed for four years and three months.

Harford kept 10 per cent of the proceeds from the invoices, while Swann kept the rest, buying a fleet of luxury cars, boats and properties.

The judge ordered Swann to spend at least four years and six months in prison before being eligible for parole.