Outreach crews working with the homeless say the current cold snap is putting lives on the line.
It comes amid reports that some shops and cafes in Dublin and surrounding counties are refusing to fill flasks with hot water, and moving homeless people on as they try to keep warm.
Inner City Helping Homeless CEO Anthony Flynn is call calling on the Housing Minister to urgently mobilise the winter beds initiative.
"The council haven't initiated a cold winter initiative. The cold winter initiative should be initiated from September on.
"We've continuously asked for 150 beds to be put into the system over the last three months, we've requested the Minister do that.
"We're hearing that there's hostel closures around the city over the last two weeks and that those numbers are being made up by additional beds being put into the system but the extra 150 beds that we're looking for are not actually being put in."