Inland Revenue has signed a seven-year contract with Hewlett-Packard for desktop upgrade and support.
The department is currently using a mixture of Windows and Novell technologies.
An Inland Revenue spokesman says the desktop upgrade project is centred on a refresh of the desktop and infrastructure environments to ensure they remain current and are supported while improving service availability and performance.
There are 5800 staff working at Inland Revenue throughout New Zealand.
The spokesman says the price of the contract is commercial in confidence.