The state of Queensland has joined a high court challenge against the Australian government's mining tax.
Fortescue Metals Group lodged the case last month, claiming the tax unfairly discriminates against certain resource rich states.
The tax came into effect on 1 July and is expected to raise $A13 billion over the next four years.
The ABC reports the challenge threatens the federal government's plan to deliver a budget surplus next year.
Constitutional experts have suggested it will be a difficult case to win, but Queensland Attorney-General Jarrod Bleijie says it will be worth it.
Mr Bleijie says the decision to intervene is about investment in the state.
''We are one of the biggest resources states in Australia along with Western Australia, so it's important we protect that and do everything we can to protect that as much as we can,'' Mr Bleijie said.
''The more the federal government intervene in the way they do business, the less people they're going to employ - and that does impact Queensland.''