Greens environment spokeswoman Rosalie Woodruff appeared at Monday's inquiry hearing and said legislation needed to be changed to allow for the Environmental Protection Authority to be more independent and for the Marine Farming Review Panel to be more transparent.

"The legislation governing the EPA and the marine farming review panel means they are not able to operate independently of government," she said.

"All their decisions are influenced and formally direct by government policies and priorities as well as formally overseen by ministers who can make final decisions."

Dr Woodruff said there was no way to appeal decisions made by the EPA or marine farming panel.

EPA head Wes Ford is due to appear at the inquiry on Friday.

Committee chairwoman Meg Webb asked Primary Industries Department acting-secretary Tim Baker earlier in the day about why there had not been an independent assessment to plan where fish farms would go.

Mr Baker said the department was constrained in what it could do in terms of marine farming development plans.

"It's the department's role to implement the rules as per the legislation and the government's policy," he said.

"It's not our role to comment on what the government's policy should or shouldn't be."

The inquiry heard last week of issues to do with marine debris produced by fish farms.

Mr Baker said the number of compliance officers, within the department and Marine and Safety Tasmania, to deal with the issue had increased.

"I think it's a fair expectation that as the industry grows there will be continued need to continue to resource it," he said.