Moves to put an end to the increasingly fractious matter came as it was revealed that ACTEW's Cotter Dam project has been hit with a further delay and cost increase.

The Legislative Assembly will be told next week that the cost of the dam has increased from $405 million to $409 million and the deadline for completion pushed back three months.

ACTEW managing director Mark Sullivan, ACTEW chairman John Mackay and ACT Chief Minister Katy Gallagher held a meeting on Tuesday after Mr Sullivan earlier revealed he had offered to take a pay cut.

Ms Gallagher has criticised the under-reporting of Mr Sullivan's salary by $234,000 in an ACTEW annual report and a letter to the shareholders in 2011, which both stated his remuneration package was $621,171 when it was in fact $855,000.

Mr Mackay has described the error as an 'honest mistake''.

Ms Gallagher said after Tuesday's meeting it was not her job to even consider Mr Sullivan's offer of a $140,000 pay cut.

It was the role of the board of the utility to set Mr Sullivan's wage but she had asked for reassurance that the managing director's pay level was appropriate.

On Tuesday morning, Mr Sullivan addressed the controversy with a combative radio interview attacking media outlets including The Canberra Times and describing the coverage as "tripe".

He revealed he had offered to take a pay cut but that Ms Gallagher had referred the suggestion back to the board.

"You can't do more than that … it was quite surprising to have it rebutted," Mr Sullivan said.

The under-reporting of his salary was a mistake that had cost ACT taxpayers nothing,'' he said.

''The error in disclosure makes no difference to taxpayers' money … the money was spent, the money was accounted for, the auditors have said there's no material error," he said.

"It is an error in disclosure, it is not an error in fact."

Ms Gallagher said she had received the pay cut offer and sent it back to ACTEW's board.

"The shareholders received a response from the chair of the board around possible changes to the remuneration arrangements for the managing director," she said.

"We're certainly not in a position, I think, where politicians should be forming views or changing people's remuneration.

"That's not the shareholders' job.

"We've made it clear from the beginning that we expect the board to do that … and we expect that to be informed by independent analysis of the job and that we expect it to be in line with industry benchmarks for the job."

Ms Gallagher said that she had agreed with ACTEW to hold a special general meeting of the board and the two shareholders, The Chief Minister and the Treasurer, in an effort to resolve the issues.

"The next step is to have a special general meeting of the board and close the matter," she said.

The statement to the Assembly on the Cotter Dam will confirm the project cost has climbed to nearly $410 million and that its deadline has been pushed out by an extra three months to July.

In a statement on Tuesday night, Mr Sullivan defended the Cotter Dam delay and overrun.

''Despite the complexities of this project we have a relatively small increase, of less than 1 per cent, to our estimated cost to complete it. It should be noted that this is not a new budget and we are still driving to meet the approved budget as closely as possible,'' he said.

''We are also very pleased that if the project were to come in at the higher cost it will be more than offset from the further saving of over $6 million on the Murrumbidgee to Googong Water Transfer project.''

In the statement to the Assembly, Ms Gallagher and Treasurer Andrew Barr say the dam's April completion date has been set back to July 2013 because of high winds and frost in 2012.

ACTEW's board says the increase is still within 1 per cent of the $405 million budgeted last year.

But Opposition Leader Jeremy Hanson said the latest increase was "extraordinary" after repeated assurances from ACTEW that the costs would not escalate further.

In March 2012, floods pushed the dam's budget out from $363 million to $397 million.

That figure was revised to $405 million in April last year.

"That the original estimates were in the order of $150 million and the project is now $409 million is, by any measure, unsatisfactory," Mr Hanson said.

"Ultimately it is the people using water in the ACT that are going to pay the price for this."