A former Mighty River Power engineer has been found guilty of ripping the company off to the tune of around $2 million.

His estranged wife sobbed as she was also found guilty of assisting his fraud.

Paul and Jane Rose were separated in the dock by a security guard as the jury's verdict was read this afternoon.

Paul Rose was responsible for buying parts and organising services for Mighty River Power.

The court heard he secretly set up three purchasing companies that added a large mark up to each item before selling them to Mighty River.

Prosecutors said Jane Rose knew what was going on and actively aided him.

The pair will be sentenced in April.