Australia’s Construction, Forestry, Mining and Energy Union (CFMEU) has said it will launch a Federal court bid to block Rio Tinto from moving Australian workplace agreement workers into a five-year agreement before the Fair Work Act becomes law on 1 July.

Under the new agreement hundreds of miners would lose their right to bargain for future wage increases and improved conditions as their existing agreements expire.

CFMEU WA secretary Gary Wood said the mining giant had forged the workplace agreement in a bid to circumvent the government’s new industrial relations (IR) laws.

“Rio Tinto has deliberately moved to dodge its obligation to recognise the right of its workers to bargain for future pay increases and improved conditions under [Prime Minister] Rudd’s new IR laws,” Wood said.

CFMEU general secretary Andrew Vickers added that the union was prepared for a “long legal battle”, and vowed to fight for the right of Australian miners to bargain under the Rudd Government’s new workplace laws.

The case will be the first of its kind in Australia.