Energy giant AGL has been found to have breached its licence conditions multiple times but has escaped prosecution.

The company, which has a market capitalisation of $8.7 billion, has been fined $4000, allowed to sign an enforceable undertaking and ordered to pay $150,000 to a environmental education program instead of facing legal action from the Environmental Protection Authority.

Mark Gifford, the EPA chief environmental regulator, said an audit of the Rosalind plant at Camden found several non-compliances but they were not considered a significant environmental risk.

The audit, which found instances of failure to monitor air pollution, failing to manage water pollution and exceeding oxides of nitrogen (NOx) emission limits, came as part of the EPA’s preparations to regulate the wider coal seam gas industry. 

But Greens MP Jeremy Buckingham said the EPA has to explain why it has failed to prosecute a serial offender. He said AGL has breached its licence without meaningful penalties because the EPA has been derelict in its duty.

“It’s clear from the tone of the EPA’s press releases and public statements that they play down any incidents. The EPA can’t just continually be an apologist for polluters," Mr Buckingham.

Mr Buckingham, who is the deputy chair of a parliamentary inquiry which is investigating the performance of the EPA, said one of the breaches which polluted the air with oxides of nitrogen had serious health consequences for those exposed.

"It’s an embarrassment to the EPA that this has been happening near suburban Sydney with virtually no consequence,” Mr Buckingham said.

Opposition environment spokesman Luke Foley successfully moved for the Upper House inquiry, which last week called for public submissions ahead of public hearings. 

AGL group general manager Mike Moraza said the company takes compliance with its licence seriously.

"Since receiving the draft EPA audit report in January we have undertaken thorough reviews and addressed the issues raised,” he said.