The clock is ticking on the Assembly's stalled bid to implement welfare reforms, with failure to introduce the legislation set to be a very expensive choice, the Secretary of State has warned.
Theresa Villiers' remarks come on the back of cautionary statements from the Treasury that if the proposals are not enacted by January the Northern Ireland block grant will be "adjusted".
The proposed changes to the welfare system, which have already been implemented in the rest of the UK, have been the cause of intense political debate in Northern Ireland, in particular the controversial so-called "bedroom tax".
The measure targets benefit recipients who are not deemed to be utilising all the bedrooms in their property.
If the changes are ultimately adopted in Northern Ireland, around 32,650 (52%) of working-age housing benefit claimants in the social housing sector are set to receive less money.
Opponents of the proposal insist the make-up of the social housing stock in Northern Ireland would mean many of those impacted would not be able to downsize to smaller properties. They also claim it would cost more to administer the change than the money it is designed to save.
The bill's passage through the Assembly hit the buffers earlier this year, with MLAs unable to reach consensus.
Sinn Fein and the SDLP have voiced vehement objections to the "bedroom tax" and have threatened to support a petition of concern mechanism that would effective veto the proposals.
DUP Social Development Minister Nelson McCausland, who has also voiced concerns over elements of the bill, has been attempting to formulate Northern Ireland-specific alterations to the legislation that would still enable the legislation to be introduced without breaking the so-called "parity" principle on costing.
But as yet there is no sign of a resolution to the political impasse.
Ms Villiers urged MLAs to adopt the bill.
"Well the clock is certainly ticking on welfare reform," she said.
"It is a matter for the Executive whether they choose to adopt the same welfare reforms as is the case in the rest of the UK or whether they break with the parity principle that is applied in Northern Ireland over many years.
"It would, I have to say, be a very expensive choice for them if they wish to break with parity."
She added: "It would be a very big decision for them, it would have a significant impact on them financially.
"And I will continue to work with the Executive and promote and press the case for adopting the welfare reform that we have in the rest of the UK in Northern Ireland as well.
"We have worked very hard to ensure that we take an approach to welfare reform which is fair both to the people who are in need of support in the system and taxpayers.
"Welfare reform is never easy but we do believe there is significant public support for changes to welfare which really is designed to ensure that work always pays, to incentivise work - that commands a lot of popular support.
"We are also very clear that it is vitally important that those who need support continue to get it.
"So I believe there is a strong case for welfare reform on its merits and that case I will continue to make with the Executive and I very much hope that ultimately they do decide that they will adopt the same welfare reform approach and, as I say, if they choose not to then, yes, unfortunately that does mean that it would have an impact on the block grant."
A spokesman for the Department of Social Development said: "Minister McCausland remains fully committed to taking the Bill through its remaining legislative stages.
"However, he cannot move the Bill towards the consideration stage (next step of the bill's legislative passage) until there is sufficient consensus within the Assembly.
"Funding of social security benefits in Northern Ireland is provided from the Treasury. If Northern Ireland does not progress welfare reform, this could lead to adjustment to the NI Block."