Pro-life campaigners are poised to take legal action if the UK government moves forward with plans to expand abortion services across Northern Ireland.
Westminster voted through drastic changes to abortion regulations in the province while Stormont was suspended, but the services are yet to be commissioned.
Secretary of State for Northern Ireland, Brandon Lewis, is expected to announce the next step in the implementation of the changes on Thursday.
The Abortion (Northern Ireland) Regulations 2021 give Mr Lewis powers to bypass locally elected politicians and direct Stormont ministers - including health minister Robin Swann - to implement a "fully-funded abortion service".
The Society for the Protection of Unborn Children (SPUC) has raised £100,000 towards a judicial review into the validity of what it calls a "devolution power grab" by Westminster.
While the legal action is not scheduled to take place until October, SPUC said it was "ready to go to court within hours" to stop Mr Lewis issuing directions before the case can be heard.
The Northern Ireland Office has responded to the threat by saying fresh legal action would be "inappropriate and unnecessary" because abortion services will not be commissioned until next year.
In a letter, it said, "The immediate effect of the direction will be that work needs to be carried out by the Department of Health before services will be commissioned in practical terms and the direction will take account of the commissioning time required.
"The direction will therefore result in the commissioning of those services some time in 2022 rather than in the immediate period prior to the currently listed hearing date.
"Although the direction does make provision for interim services this only includes ongoing support for the services which are already in place in Northern Ireland and as such maintains the status quo rather than changes it ... an application for interim relief is unnecessary, and if made should be refused."
In a letter to Mr Swann, SPUC's lawyers urge him not to act on any directions from Mr Lewis until the completion of the judicial review. It also asks him not to act without approval from the Executive Committee.
Liam Gibson, SPUC's NI Political Officer said: "If this power grab by the Westminster Government is allowed to stand it will condemn to death an untold number of unborn babies and also fatally undermine the devolution settlement.
"London is stripping locally elected Ministers of power and denying the people an accountable government with a democratic mandate.
"The situation means that enormous powers have been vested in a politician who is not answerable to the people of Northern Ireland."
John Deighan, SPUC's deputy CEO added: "These are the most challenging times the pro-life movement has ever faced in Northern Ireland.
"We need the prayers of pro-life supporters and their financial assistance too as we seek to raise the funds required to finance these court cases."