Salvation Army Oasis Centre counsellor Chris Watkins said games such as Slotomania, on Facebook, were encouraging people into real gambling and slot machines.
Problem gamblers were coming to Oasis counsellors at a rate of 20 to 25 a week and many of them had lost tens of thousands of dollars.
''These people have lost everything ... and we know the problem is a lot worse,'' Mr Watkins said.
One way of dealing with the problem was for problem gamblers to voluntarily include their name on a list of people banned from local gambling establishments.
About two people a week were doing that.
The issue of youth gambling would also be tackled in the Choice Not Chance Local Legends Community Festival in Dunedin next Friday.
Rapper Scribe will headline the festival that aims to celebrate the creativity of Dunedin's young people and increase awareness of gambling harm.
Mr Watkins said Scribe would perform live and share his own story.
Dunedin MC Beau Jeffries and other music, poetry and dance acts would also perform, including part-time poet Grant Kingi (19).
Mr Kingi, a University of Otago psychology student, said he had not had a gambling problem himself but it had affected his parents when he was growing up.
''People find it hard to find jobs and are looking to find money in other means.
''It seems like they have no choice but to revert to gambling.''
He said people should not feel ashamed and should get help if they thought they had a problem.
The Choice Not Chance Local Legends Community Festival is on next Friday, at the Glenroy Auditorium, in the Town Hall, from 10am to 2pm.
