Labour unions have threatened strikes if copper giant KGHM is privatised after Poland’s Government announced it may sell 10% of its stake.

The prime minister’s economic adviser Michal Boni said that the proposal will only see KGHM privatised to an appropriate level and that the government would remain the majority stakeholder with just over 30% of shares, AFP reports.

The possible sale is part of the treasury ministry’s $12.7bn privatisation plan to raise money to reduce growing budget deficits.

The ministry’s original plan to sell the entire 42% stake in the group was earlier rejected by prime minster Donald Tusk following criticism from coalition members and unions, Reuters said.

The transaction is expected to raise up to $600m, Reuters said.