The Labor party has joined the Greens in their push for a Senate probe into environmental offsets for mining firms, questioning whether the price they pay is really equal to the damage they produce.

A vote on the proposed inquiry is expected this week.

The Greens launched the bid to investigate offsets for the Abbot Point coal port expansion in Queensland, based on concerns about the impact of large-scale dredging on reef health and water quality.

A requirement has been imposed for the North Queensland Bulk Ports Corporation, the group behind the expansion, to offset the fine sediment released into the water by a measure of 150 per cent.

Greens Senator Larissa Waters said she hoped the inquiry would go through, and investigate measures taken by other major coal mines in Queensland and New South Wales.

Ms Water says it is time to give the ailing environment a higher value, and require more from the groups seeking to exploit it.

“When you have the last remaining patch of wilderness in an entire region or a stand of endangered box gum woodland, I think the community needs to have their say on whether it's appropriate that that simply be destroyed by yet another coal mine,” she said.

She said the push is not a move against mining itself, but an effort to ensure offsets are actually doing what they are intended to do.

“The terms of reference for the inquiry are broad enough to improve offsets that have been imposed no matter what the development project is, so it is certainly broader than mining,” she said.

“We don't back away from the fact that the community has raised this as an issue.”

If successful, the inquiry would report its findings by mid-June.

Environment Minister Greg Hunt says the offset system was set up under Labor, and operates as it should.

“The offsets' policy and guide was introduced under the former Government,” he said.

“The process of developing offsets is open, transparent and has bipartisan support.”