The national reporting service for suspected illegal content on the internet has dealt with the second largest number of reports in a single year since its establishment 17 years ago.

The number of suspected cases notified to Hotline.ie in 2015 rose to 3,153 during 2015, a 35% increase on the previous year's total.

Within that suspected cases of Child Sexual Abuse Material or CSAM increased by 4% to 327.

According to Hotline.ie, 70% of the suspected CSAM cases in 2015 depicted boys, up from 42% in 2014.

The organisation said this challenges the misconception that girls are most at risk of sexual abuse, although it acknowledges that the international evidence is that boys are less likely to be the subject of CSAM images than girls.

Of the 327 suspected cases of CSAM reported to Hotline.ie last year, it is thought that only one was hosted on a computer or website in Ireland.

Since the organisation began its work in 1999, 28 suspected cases have been found to have been hosted within this country.

Hotline.ie says one report to it usually constitutes multiple images or videos, with 95% of the boys depicted being abused aged between four and 13-years-old.

Hotline.ie was set up by the Internet Service Providers Association of Ireland under an agreement with the Department of Justice and An Garda Síochána and oversight from the Office for Internet Safety to act as the central reporting point for suspected illegal content on the internet here.

However, the body says urgent situations where people may be in immediate danger should be reported directly to gardaí.

The organisation is part of a pilot network of 12 organisations coordinated by The International Network of Internet Hotlines in partnership with Interpol that works together to track, trace and stop those making and distributing CSAM, a task made more difficult by the widespread use of the Darknet.

Last year Hotline.ie sent 146 CSAM reports to eight counterparts elsewhere in the world, and three others to China and Singapore through law enforcement channels.

The report was launched by Minister of State for Justice, David Stanton, in Dublin this morning.

"Public reporting is an essential element in making the Internet a safer environment for all users, particularly children, not just here in Ireland but around the world," said Mr Stanton.

He added: "All of us who are concerned with protecting our society, and particularly our children and young people from illegal and harmful use of the Internet, from teachers, to legislators, and above all parents, must be ever vigilant and ready to take necessary action."