The organisation's 300-strong team of call room volunteers fielded 34,877 calls in the 2015-16 financial year, 19,098 more than in 2010-11.

Acting chief executive Pauline Thorneloe said women called more often than men but it was factors such as social estrangement and unchecked mental health concerns that were most prevalent.

This year marks a 45-year milestone for the telephone crisis support service in the capital.

Ms Thorneloe said Lifeline Canberra was an example of people power in action, receiving just eight per cent of its funding from the ACT government, and feverishly fundraising to sustain its operations.

In the crisis support sector she said there was a grave human cost to not keeping up. However, year on year staff had been able to do more with less.

"We now nationally have an 85 per cent answer rate," she said. "The demand is more than the number of volunteers across the country we have. It's a frustration for us because we are limited in what we can do based on the resourcing," she said.

Lifeline Canberra has just launched Save a Seat – a campaign that asks the public to think about the empty spaces left in homes and communities after suicide and explains that a $26 donation can keep one support worker in a Lifeline call room seat.

Mike Macnamara trained with Lifeline Canberra in 2010 and after six years continues to carve out time in his week to lend an ear as a volunteer.

In 2015 about 5000 of the 30,000 crisis calls Lifeline ACT answered related to suicide and 38 Canberrans took their lives.

Mr Macnamara said it was vital there was someone to pick up the phone for the thousands of others.

"It's a hugely negative thing for a society to have people who reach the point in their lives where they commit a suicide," he said. "That Lifeline has lasted for 45 years indicates very clearly the demand in the community for its services."

Chris O'Sullivan suffered depression and found talking to people without fear of judgement was vital.

"I felt fortunate to have people around me but over time I have acknowledged a lot of people don't," she said. "Giving my time and doing that for someone was a way to give back."

As mental health concerns and rates of suicide continued to rise across Australia, she said having the tools to intervene and let someone know they weren't alone was very rewarding.

If this story has raised issues for you or someone you know, you can call Lifeline on 13 11 14.