There is outrage over reports that one state government water body spent over $400,000 on some corporate advice.

A TasWater spokesperson has responded to union condemnation after it was found that the company paid specialists $435,000 to develop a new corporate structure.

The agency says the costs were incurred as part of a big restructure, merging three regional bodies owned by Tasmanian councils into the unified TasWater.

ACTU-affiliated union Professionals Australia says it has leaked documents showing TasWater paid the money to Marchment Hill Consulting.

But the allegations of over-spending come at a time when the union and TasWater are mired in a fight over a new enterprise agreement.

TasWater has now defended its outlay.

“The use of short-term specialised services ensures TasWater operates as effectively as possible and has the resources to invest in water and sewerage services that the Tasmanian community deserves,” a spokesperson said.

“This has been a complex restructure and TasWater has met its savings targets for the last financial year and is on track to meet future targets.”

Professionals Australia Tasmanian director Luke Crowley it adds to the pile of big spending by the agency.

The union claims that in addition to other consultation fees, TasWater had also spent over $1 million on consultants in the past year.

“If it doesn't translate into increased water prices, it will translate into poorer service,” Crowley said.

It comes just weeks after the same group attacked TasWater for paying more than $280,000 to HR consultants to conduct interviews for senior company roles, and for paying about $50,000 for consultants to help HR reps in enterprise agreement negotiations.

An internal memo was recently leaked to the media, which warned staff that they would be dismissed if they were found leaking confidential documents.