The Senate has voted to hold another inquiry into the Federal Government's mining tax.

The Greens and Coalition joined forces to set up the inquiry into the design of the tax and why it has failed to collect the amount of revenue forecast by Treasury.

The tax raised $126 million in its first six months, well below the yearly forecast of $2 billion.

The Greens say the new inquiry is a win for transparency and the community.

Liberal senator Mathias Cormann also welcomed the inquiry, but said its outcome would not change the Coalition's view that the tax must be repealed.

"The mining tax is a bad tax which should be scrapped and nothing in this inquiry will change our mind on that," he said.

"However we do think there is a public interest in pursuing through a further inquiry [into] the reasons why the mining tax has come in more than 90 per cent below the revenue estimate."