Queensland Deputy Premier Jeff Seeney has denied giving special treatment to a company that had donated money to the Liberal National Party (LNP).

Karreman Quarries was being investigated over unlawful sand and gravel extraction from the Upper Brisbane River.

The company was facing legal action by the Department of Natural Resources and Mines when an amendment slipped unnoticed into a package of reforms to the state's Water Act that retrospectively legalised its activities.

The change was not mentioned in the bill that preceded the vote on the amendments and the Queensland Opposition knew nothing about it.

The company of prominent Queensland businessman Dick Karreman has given $75,000 to the LNP in recent years, making it one of the largest donors to the party.

Mr Seeney does not deny changing the law to benefit a quarrying company, but denies it was a favour because the business had donated money to the LNP.

He says the business raised the issue with the State Government and an amendment was passed so it could continue to operate.

"It will affect anybody who has a pre-existing right to extract sand and gravel from that situation and I don't know of any other compliance notices that have been issued," he said.

"But I know of many other examples of operations that could be easily in the same situation."

The law change means officials are no longer able to prosecute the company and also means the company's activities at Harlin, worth more than $15 million annually, can continue unimpeded for another five years.

The amendment specifies the type of extraction of quarry material for which Karreman Quarries was under investigation "is lawful, and is taken to have always been lawful".

Emails to farmers at Harlin from the Department of Natural Resources and Mines, seen by the ABC, show that officials had obtained a stop notice against Karreman and were gearing up for legal action to enforce it when the surprise amendment was made to the law.

Law changes need 'transparency and accountability'

Jo-Ann Bragg, from the Environmental Defender's Office, says there should have been a public debate before a law was passed that benefited a company that donated money to the LNP.

Ms Bragg says the last-minute changes need greater scrutiny.

"We need transparency and accountability for changes to the law like this, especially where they're retrospectively validating unlawful activity under the Water Act," she said.

"In this case where the quarry owner was a donor to the LNP, it's even more essential that that should be brought out into the open."

Quarrying causing erosion, expert says

Mr Seeney has also fended off landholders' claims the extraction caused erosion, citing recent floods.

"It's a natural process," he said.

"It's also natural for people who are disaffected by that process to seek to point the finger at somebody to blame.

"We have to be very careful that we make sure that what's happening in river systems all over Queensland isn't used to close down a business that's been operating for 20 years."

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But Professor Jon Olley, a fluvial geomorphologist at the Australian Rivers Institute at Griffith University, said there was no doubt that quarrying was causing erosion.

"By disturbing the bed of the channel and the banks of the channel you actually trigger erosion upstream and in effect, mining farmers' properties upstream," he said.

"They've lost many hundreds of thousands, if not millions of dollars worth of land that they can't get back.

"It's basically gone, it's a resource that they've lost."

LNP 'always planned' to wind back Labor's quarrying laws

The institute warned in 2007 that sand and gravel extraction on the Upper Brisbane River, which feeds Wivenhoe Dam north-west of Brisbane, was unsustainable and should cease altogether.

A law firm acting for the company says when Mr Karreman met the Deputy Premier in December, he had not discussed the investigation. ( ABC TV: 7.30 - file image )

Responding to questions from the ABC TV's 7:30 program, a law firm acting for Karreman Quarries said allegations about the lawfulness of the company's operations and their impacts had often been made without a full appreciation of the legal position and had included factual inaccuracies.

The firm said when Mr Karreman, the company's managing director, met Mr Seeney in December, he had not discussed the investigation into the operations in the Upper Brisbane River or changes to the Water Act.

In a statement, Queensland Natural Resources Minister Andrew Cripps told the ABC the LNP had always planned to wind back reforms enacted by the previous Labor government relating to river quarrying.

Mr Cripps said the issuing of a compliance notice to Karreman Quarries, in accordance with legislation as it stood at the time, had only drawn its attention to the need for new arrangements.

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