A senate committee says Tassal should not be found in contempt of an inquiry into the aquaculture industry.

The Standing Committee of Privileges (SCP) is designed to review conduct that may obstruct the Senate's work.

Claims that Tassal representatives had “improperly influenced a witness” were referred in January to the SCP.

It came after media reports in November 2016, alleged Tassal “bought” the silence of Dover farmer Warwick Hastwell over contamination claims.

Mr Hastwell told reporters he had accepted a deal from Tassal.

The SCP said it broke the issue down into two parts.

“The committee has been charged by the Senate to establish, in the first instance, whether there was any attempt to improperly influence Mr Hastwell and secondly, whether any such action may constitute a contempt of the Senate,” it said.

The SCP said that on the evidence provided, it was “unable to conclude with any certainty that Tassal sought to influence Mr Hastwell, either in his decision to appear before the committee, or in the evidence that he might give to the hearing”.

It did raise some concerns about the commercial negotiations between Mr Hastwell and Tassal representatives.

“The committee is concerned that reference to evidence to the fin-fish aquaculture inquiry appears to be commonplace during the negotiations, together with references to media campaigns and legal action,” it said.

“Decisions about whether to give evidence and/or what evidence a witness might give should not be used as currency in commercial negotiations.”

It said Mr Hastwell’s concerns should have been made to the Senate directly.

“As a matter of practice the committee would encourage those who feel unable to provide evidence to a Senate committee inquiry because of outside pressure to inform that committee of the circumstance so that the facts can be established contemporaneously.”