The government has a Select 5.0 software licensing programme, which expires on 30 November.
The Select software licensing programme is designed for corporate, government and academic customers with mixed product and purchasing requirements. The Norwegian contract is available to public institutions at the national, state and local level with more than 400 workstations.
The public institutions can order products from the US software company at a discount, but are not required to, he said.
In Norway, Microsoft has up to 95% of the government market for some types of applications, according to a government spokesman.
The use of open source software, such as the Linux operating system, could promote competition, the spokesman said.
By choosing not to renew the contract with Microsoft, "the government is sending a signal to other software companies that it is open to alternatives", the spokesman said.
The Norwegian government hopes to announce a new public sector IT strategy new strategy in October or November.
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