The Samaritans of Singapore (SOS) need your help. It has insufficient volunteers to man the suicide-prevention centre's 24-hour hotline, so more calls are going unanswered.

Ms Christine Wong, executive director of SOS, told The Straits Times ahead of World Suicide Prevention Day 2017 yesterday that there has been a "significant" dip in the number of calls answered by Singapore's main suicide hotline.

Last year, 35,832 calls were taken, compared to 39,310 in 2012.

While the number of trained volunteers has remained stable over the years, the demanding nature of many full-time jobs means volunteers have less time to be in the SOS office to take calls, she said.

Of the 173 volunteers on SOS' database as of last year, only 59.8 per cent could fully commit to the hours required of them, which includes some overnight duty.

Most calls come in between midnight and 2am - which is also when there are fewest volunteers.

SOS receives 100 to 120 calls every day and there is not always someone available to take them.

Ms Wong said SOS used to have a number of volunteers who were stay-at-home expatriate wives but, these days, they also work.

Then there are a few who, for various reasons, leave SOS immediately after training and never fulfil their commitment.

If the trend of dwindling numbers of active volunteers continues, the not-for-profit organisation might have to consider employing more staff, or reassess if it can run the hotline round the clock. Ms Wong noted: "This is a worldwide issue with all hotlines and not unique to Singapore."

The odd hours and emotional toll of listening to people in dire straits mean that many volunteers do not stay for long, a long-time SOS volunteer told The Straits Times. The retired nurse, 61, who has taken calls at the hotline for about 10 years, admits that there are times when she feels "very overwhelmed".

"Anyone with the desire to help people, just listen and be empathetic, would be excellent (as a volunteer). The training is excellent, the commitment is very transparent, and it's flexible: You can choose when you want to volunteer."

Mr Jonathan Siew, assistant director of Care Corner Counselling Centre, said the centre has about 130 volunteers managing the counselling hotline from 10am to 10pm throughout the week.

While there has not been a sharp fall in numbers, the centre has found it difficult to recruit volunteers in recent years as most people are attracted to voluntary work that doesn't require long-term commitment, he said.

Mr Siew added: "We are looking at the possibility of expanding the hotline service to support more callers, but it is challenging to get people to volunteer for the hotline."

A total of 429 people took their lives last year, up slightly from 409 in 2015, 415 in 2014, and 422 in 2013.

Over the weekend, some organisations commemorated World Suicide Prevention Day 2017. On Saturday, Shan You Counselling Centre ran a suicide awareness training session for the public called safeTalk: Suicide Alertness for Everyone.

A 64-year-old retired engineer who volunteers at the centre's Mandarin-speaking Yuan Yuan Helpline for four hours a week said about 10 per cent of the calls he fields are from suicidal individuals.

Ms Celestine Chua, a counsellor at the centre, stressed that training the public to look out for warning signs in loved ones was important, since not every suicidal person would call a helpline.

"Instead of waiting for suicidal individuals to come to us, we are trying to train people in the community to look out for (warning) signs and render support," she said.