A bill extending the in-work tax credit - at present only paid to parents in paid work - to beneficiary and student families looks likely to fail.
The House rose on Wednesday before a vote could be taken, but it is unlikely to pass, with opposition from National, ACT and United Future.
The bill's sponsor, Green Party co-leader Metiria Turei, says she's disappointed United Future's Peter Dunne withheld his support, as he stands on a family-friendly platform.
Mr Dunne says he supports the principle of giving families an incentive to work, and he believes the bill removes that incentive.
