The Australian Tax Office has cut over 70 per cent of its workers from the area responsible for collecting the minerals resource rent tax (MRRT).

Reports say less than 40 people are left in the area of the ATO that collects the tax from the biggest companies operating in Australia.

It is no secret that the Coalition government has the MMRT in its sights, but the bill to repeal it still faces strong Senate opposition before it can come into place.

The MMRT repeal was rejected in late March, opposed by Labor, the Greens and the Palmer United Party.

The opposition of the Palmer party surprised many, as party leader Clive Palmer is impacted by the tax in his private capacity as a mining magnate.

But Palmer has refused to back the bill until the Federal Government reverses its decision to cut payments for children of fallen defence personnel.

By law, the ATO must continue collecting the MRRT until such time as a repeal bill is passed, but it has already clearly started winding-down work in that area.

Stephanie Martin, a deputy commissioner at the Australian Taxation Office, had been heading the ATO’s resource rent tax team, but has resigned and not been replaced since early March.

Seven West Media outlet The West Australian is reporting that only 30 staff are now dealing with “active compliance and technical advice” for the MRRT. They are also in charge of collecting the petroleum resources rent tax, which is expected to bring in about $2 billion.

Shadow assistant treasurer Andrew Leigh says the reduction of tax officers on the job is the government doing all it can to undermine a tax it does not favour.

“To score a cheap political point, this government is cutting back on enforcement of the mining tax, which Joe Hockey projects will raise $1.8 billion in 2016-17,” Leigh said.

“Every dollar foregone means higher taxes or fewer services for ordinary Australian families.”