It is an 'absolute disgrace' that Ireland still has no laws against 'sex for rent' arrangements.
Legislation to criminalise the behaviour is being introduced into the Dáil by Sinn Féin.
Research shows that 5% of international students have either seen an ad seeking sex for rent or have been directly propositioned.
The Irish Council for International Students (ICIS) Executive Director Laura Harmon told Newstalk Breakfast the law should have been changed by now.
"It's completely necessary to legislate for this," she said.
"Actually, I'm quite shocked; it's an absolute disgrace that we don't have this legislation in place.
"It's something that the ICIS has been calling for, for over two years now.
"There was a previous bill that the Social Democrats introduced which didn't pass through the Oireachtas.
"We'd be worried that the same might happen with this new Sinn Féin bill but we certainly welcome it.
"Ultimately it's up to the Government to act on this".
'Not a criminal offence'
Ms Harmon said some adverts can be quite underhanded.
"It can be very insidious what's put online," she said.
"Often the ads will say [a person] 'must be open-minded' - which if English isn't your first language it'd be very hard to interpret what does that even mean - 'must be open to having fun in the house' or 'must be up to sharing a bed'.
"Often times... they might meet up with the landlord or go to view this place and then they might actually realise what the case is.
"They might just see one bed... and it's been said to them 'You'd be sleeping in the bed with me'.
"Or it might be a case that they might say, 'We could have an arrangement and the rent could be free'.
"The key thing here is that this isn't a criminal offence, so there needs to be an offence created through law to clamp down on this.
"This isn't just creepy behaviour we're talking about; this is extremely dangerous predatory behaviour".
'Shadow housing crisis'
Ms Harmon said adverts often appear on social media where there is no regulation.
"I think with the housing crisis in this country there's what we see and what we can't see," she said.
"So, there's very much a shadow housing crisis happening and unfortunately, there isn't a lot of data," she added.
One-in-10 international students have said that it took them more than 100 days to find accommodation in Ireland.
