The Great Barrier Reef Marine Park Authority (GBRMPA) has given details on its change of mind to approve the Abbot Point coal terminal expansion.

Authorities say they became convinced that the impacts caused by the large-scale dredging work could be offset, leading to a net benefit for water health at the port near Bowen in north Queensland.

At a Senate Estimates hearing this week, GBRMPA general manager Bruce Elliot said the group initially had doubts about the offset modelling and whether measures would actually work.

But he said after more talks with the Government, concerns were addressed.

“When we got to the end of that process after numerous discussions and swapping of correspondence in the department I was comfortable that a long-term improvement in the water quality was achievable and therefore I had no problems with that condition,” he said.

“The conditioning around the offsets did evolve over time and so by the time we got to the end of the process where we had the final proposal with the final conditions I was comfortable that the condition that was put in place was one that could be achieved.”

Some groups have claimed that GBRMPA’s worries over the impact of the dredging have been muzzled, as very little change was made to the offset protocols.

There has also been concern raised about the reporting of GBRMPA’s decisions coming through Ministerial offices, and the risk that they may be adjusted to suit political lines.

Meanwhile, GBRMPA has announced it will cut 25 jobs over the next three years.

The Authority says the redundancies are a result of the public sector efficiency dividends imposed by the previous federal government.

Five senior directors and 12 other workers have been offered redundancies, and reports say one of the directors has left already.