The amendment was proposed by Focus Ireland
An anti-homeless measure proposed by Focus Ireland as part of the Planning and Development (Housing) and Residential Tenancies Bill was defeated in the Dáil last week.
Fianna Fáil and Fine Gael are facing strong criticism for their role in blocking the amendment.
The purpose of the amendment was to make it more difficult for professional landlords to evict tenants when they want to sell the house.
In a statement, Sinn Féin housing spokesperson and Dublin Mid West TD Eoin Ó Broin said TDs had been urged to support the initiative in the weeks leading up to the vote.
"For reasons which still aren't clear Minister for Justice Frances Fitzgerald voted against the amendment", he said. "However, it was the decision of local TD John Curran and his Fianna Fáil colleagues to abstain that dealt the final blow to the amendment.
"It is deeply disappointing that John and Frances decided to block this important amendment to the Housing Bill. If enacted it would have prevented families from becoming homeless in the coming months. That is why Focus Ireland asked all parties to support it."
He added that it the move was hypocritical considering their previous expresses f concern surrounding the homeless crisis.
Mr O'Broin visited the Home Sweet Home homeless occupation of Apollo House in Dublin last Saturday. At least 20 homeless people remain at the site on Tara Street.
Independent Minister Katherine Zappone said she has concerns about the legality of the occupation, and shares the views of homeless campaigner Fr Peter McVerry.
However, she added that if no alternative is available for them, they should be left there.