An Upper House inquiry was established in May to examine the prevalence of the matter within several emergency services agencies, including the NSW Rural Fire Service, Fire and Rescue NSW, the NSW Police Force, the NSW State Emergency Service and the Ambulance Service of NSW.

Submissions are being accepted until Sunday July 23.

Inquiry committee chair Robert Borsak said in a statement on Tuesday: "We understand that some staff and volunteers of these agencies may be reluctant to make a submission.

“ There may be concerns about being further bullied or reprisals for speaking out. Individuals should be aware that they can request that their submission be kept confidential, in part or in full. They can also request that their name be suppressed".

"The committee has also written to each emergency service agency emphasising that it is essential that employees and volunteers be able to freely participate in the inquiry. Any adverse action taken against a person for making a submission will be a serious matter the committee will consider. Indeed it may considered a contempt of Parliament," he said.

Individuals concerned about participating in the inquiry can contact the secretariat  on (02) 9230 2895. The inquiry webpage www.parliament.nsw.gov.au/emergencyservices has fact sheets to help with writing a submission and confidentiality concerns.

The committee will also examine the adequacy of support given to victims within these agencies, particularly support given to individuals with mental health issues resulting from workplace trauma.

It plans to start hearings in September. Mr Borsak said: "The committee can consider having confidential hearings if necessary. This is not uncommon where we need to hear from people who have concerns about giving evidence in public. While confidential evidence cannot be referred to in our report, it can be used by the committee to identify systemic issues within these emergency services agencies".