Volunteers at crisis support helpline Lifeline are asked to enter the "main reason" for a call when dealing with people seeking help, and one of the options now reads "2016 Marriage Equality Plebiscite".

A spokesman for the 24-hour helpline said the category had been "recently" introduced. It is understood categories are updated when there is an increase in the number of calls relating to the subject.

However, a spokesman for Lifeline could not confirm whether calls to the service about the plebiscite had increased, because the organisation has only just begun to collect the data.

He said the addition of a category was decided by a number of factors, "such as an issue being high profile".

"Lifeline routinely records data on issues faced by communities – be they natural disasters or key social issues," he said. "By capturing information around certain issues, Lifeline can better measure the community impact of them and ensure our services can respond accordingly."

The spokesman said Lifeline was listening "very carefully" to the community about the same-sex marriage debate and "how LGBTI and other people may be affected".

"Based on the evidence we see, we will ensure that our service delivery does all it can to help people who may be impacted," he said.

Citing operational reasons, the spokesman would not be drawn on whether staff had been trained specifically to deal with calls about the plebiscite.

"Lifeline volunteers receive ongoing training to help them best support Australians," he said.

"However in addition to training, they may receive additional supervision, or they may be provided with information on appropriate referrals for specific issues."

Opponents of the federal government's plan for a plebiscite say a public campaign would increase the risk of self-harm and suicide in the already-vulnerable LGBTI community.

In September, a group of doctors and health workers called on the Prime Minister Malcolm Turnbull to drop the plebiscite as it might be damaging to vulnerable people.

Micah Scott, who heads Minus18 which provides mental health and peer mentoring support to LGBTI youth, said the new Lifeline category made a lot of sense.

Mr Scott said there had seen a rise in young people accessing their organisation in the past six months due to the platform given to homophobia and transphobia through discussions around the plebiscite.

"And this is before the plebiscite has even happened," he said. "It is very difficult to escape ...the negative comments that are being said.

"They spread quite easily around social media, and for a young person who is questioning their identity, who has recently come out, that can be very distressing to see.

"It informs a person's opinion of themselves and of their identity."

Anyone needing support can call Lifeline on 13 11 14.