The new law on unmarried couples who live together could open up huge legal issues for family farms, more than 700 delegates at the Women and Agriculture conference were told.
The Civil Partnership and Cohabitation Act would affect property rights and farm transfers, IFAC's Declan McEvoy warned the attendees.
"Effectively, cohabiting couples will have to be dealt with under the same laws as separation and divorce," Mr McEvoy claimed.
Under the act, cohabitants will have access to the redress scheme and the court would be able to make rulings in relation to dividing property, pensions and provisions from a deceased person's estate.
A co-habiting couple is defined as two unrelated, unmarried adults living together in an intimate relationship. They must be living together for two or more years if they have dependent children from the relationship, or five years or more if there are no children from the relationship.
Under the act, a court can make redress orders taking into account the duration of the relationship, degree of commitment and earning capacity, and the rights of children from current or previous relationships and the rights of a former spouse or civil partner.
"This act will make a lot of people in the legal profession very happy," he said.
"It is an opportunity to make plenty of fees for a very sensitive area."
The tax expert said the Fair Deal Nursing Home scheme and the Civil Partnership and Cohabitation Act would set the scene for future farm transfers.
Farmers are likely to transfer the family farm at an earlier age to avoid hefty charges under the Fair Deal Nursing Home scheme, he predicted.
The prospect of adding crippling charges to the deeds of the farm with only a 12-month repayment period for the farm heir would prompt many farmers to complete the farm transfer when they were younger and healthier, he insisted.