Hundreds of health professionals have written to the NI secretary expressing opposition to the liberalisation of NI's abortion laws.
The doctors, nurses and midwives say their consciences will not allow them to stay silent on the issue.
They want reassurance as "conscientious objectors" that they will not have to perform or assist abortions.
Unless the NI assembly is restored by 21 October, restrictions on abortion in NI will be drastically reduced.
In England, Wales and Scotland, laws that criminalised abortion were changed by the 1967 Abortion Act, which allowed an abortion to be legally carried out up to a 24-week limit.
It was also made legal beyond that in cases where the mother's health is threatened, or if there is a substantial risk the baby will have serious disabilities.
But these changes did not apply to Northern Ireland, which had its own parliament. Abortion remains illegal unless a woman's life is at risk, or there is a serious risk to her mental or physical health.
In the absence of a functioning Stormont government, in July MPs passed the Northern Ireland (Executive Formation) Act, which contained a provision placing a duty on the government to regulate to provide for access to abortion in Northern Ireland.
It comes into effect if the Stormont executive is not restored by 21 October, with regulations required to be in place by the end of March 2020.
Those who signed the letter said their concern was for pregnant mothers and their unborn children and, as Christians, it was their firmly held belief that abortion was the "unjust and violent taking of human life".
One GP told BBC News NI he and more than 700 other healthcare workers had written to Northern Ireland Secretary Julian Smith and Richard Pengelly, the permanent health secretary, to say they can no longer "stay silent" on the issue.
Dr Andrew Cupples said he was not aware of any preparation to ensure staff were prepared for the law change and insisted legal protection was essential.
He said: "The crux of this issue, if you are in that situation, is do you have the legal protection [and] moral right to say: 'I am sorry I am not happy with this, but listen, there is a fantastic service that I want to refer you to, which will get you all the help you need.'
"I want the government and the department to back me up on all of that."
The health department said it was liaising closely with NIO officials on preparations, including the development of guidance for health service professionals and the general public.
The Royal College of GPs said "conscientious objection" for staff must be protected and included in any guidelines, adding there were still many unanswered questions which could leave staff vulnerable.
Its NI chairwoman, Dr Grainne Doran, said the priority was to ensure interim guidance would be made available before October's deadline.
Meanwhile, Midwives for Both Lives - a group opposed to this change to the law - has written separately to the Royal College of Midwives, Mr Pengelly and the NIO, saying there was "currently no conscientious objection in law in NI for midwives... in contrast to our counterparts in mainland UK who are protected under law and under the NMC code".
Amnesty International's Grainne Teggart said she expected the advice from the NIO would include provision for conscientious objection.
"It should only apply to the procedure itself, not pre and post care," she said.
The Royal College of Midwives said it was "insisting that… the development of interim guidance and regulation safeguard the right to conscientious objection".
Midwives in NI should be allowed to exercise the same right to conscientious objection that can be utilised by midwives in the rest of the UK, the college told BBC News NI.
"No midwife need be involved in the direct provision of termination services if they have a moral or ethical objection," it said.
What happens next?
It is our understanding that abortion services will not be routinely available in Northern Ireland until a new legal framework is put into place by 31 March.
The UK government has said careful consideration is being given to how the interim period when Northern Ireland's criminal law "falls away" is managed.
Common sense would suggest that given abortion services have not yet been commissioned in NI, in the interim period health trusts will only be able to provide emergency care.
As almost all our questions to the various authorities remain unanswered, we can only look to the paper provided by Julian Smith to the House of Commons earlier this month for guidance.
From it we can surmise that in the interim, or limbo period, women from NI in crisis pregnancies or those "hard cases" will be signposted to either Scotland or England for terminations.
All expenses will be paid and all will happen without fear of criminalisation. Last year, there were 1,053 such cases and 12 were performed in NI because the mother's health was deemed to be at risk.
No matter what your stance on abortion - these are momentous times.