Senators warned don't 'badger or harass' witnesses

Senators have been warned to be respectful to department officials after a complaint was made about their treatment in a parliamentary hearing following fiery exchanges.

A witness in the environment and communications committee complained to the Parliamentary Workplace Support Service about how they were treated during Tuesday's hearings.

Senators were briefed on the matter following the lunch break and received a copy of the support service's guidelines on their desks.

The behaviour code for Australian parliamentarians outlined they have a leading role to play "as employers and leaders in the community" to ensure people felt safe and valued.

The code is enforceable and carries sanctions, the document states.

Committee chair Karen Grogan began the session after lunch by reminding all senators "their obligations under the behaviour code for Australian parliamentarians to treat witnesses with dignity, courtesy, fairness and respect".

"That includes not badgering, haranguing, harassing or raising your voice at witnesses, and not interrupting witnesses who are attempting to answer a question," she said.

The morning session included the Department of Infrastructure, Transport, Regional Development, Communications and the Arts and then the Australian Communications and Media Authority before the lunch break.

AAP has chosen not to name any senators or witnesses.

Senate estimates provides parliamentarians an opportunity to question a wide range of officials from government departments and agencies.