Anti-abortion group Precious Life today took the unusual step of taking out newspaper advertisements urging people to bombard their local Assembly members with protest postcards and petitions.
The pro-life campaign group bought the ads, including one in the Belfast Telegraph, in advance of a motion due to be debated in the Assembly calling for the Health Minister to abandon "any attempt to make abortion more widely available in Northern Ireland".
Director of Precious Life, Bernie Smyth, said she believes draft guidelines on abortion law in Northern Ireland, issued by the Department of Health in January, will legalise terminations here "by the back door".
"We have already distributed over 30,000 postcards across Northern Ireland for the public to sign and send to their Assembly members urging them to support the motion," she said.
"To ensure as many people as possible have the opportunity to sign the petition we have printed the petition as an advertisement in Northern Ireland's three daily newspapers - the Belfast Telegraph, The Irish News, and News Letter.
"This is unprecedented. Never before has there been such a major pro-life campaign with advertisements running simultaneously in our daily papers."
DUP MP Jeffrey Donaldson has tabled the 'no day named motion' which is seconded by fellow party MP Iris Robinson.
It says: "That this Assembly opposes the introduction of the proposed guidelines on the termination of pregnancy in Northern Ireland; believes that the guidelines are flawed; and calls on the Minister of Health to abandon any attempt to make abortion more widely available in Northern Ireland."
The motion refers to draft guidelines issued by the Department in January, before Michael McGimpsey took over as Health Minister.
Abortion is illegal in Northern Ireland unless it is deemed that the life of the mother is in danger or that the pregnancy would cause serious risk to the woman's physical or mental health.
The Department said in January it was issuing the guidance on the back of a judicial review instigated by the Family Planning Association, which sought to require the department to give guidance about the circumstances where abortion may be carried out in the province.
At the time, a department spokesman said: "There is no change or plans to change the law on abortion in Northern Ireland. The guidelines simply restate the legal position in Northern Ireland and offer clinical and good practice guidance to health professionals involved in this area."
Ms Smyth said her legal advisers had examined the guidance and said that " although the Department of Health guidelines cannot change the law on abortion in Northern Ireland, they will change how the law is interpreted".
"In effect this will legalise abortion in Northern Ireland through the back door," she added.