Two former SDLP ministers in Stormont called for change to a law banning people born in the Republic from applying for civil service jobs in the North.
Nationalist SDLP Assembly members Mrs Brid Rodgers and Mr Sean Farren, who were both born in the Republic and served in the Stormont power sharing government before it was suspended last month, argued the refusal to allow Irish citizens to apply was "illegal".
After it emerged applications from the Republic have been excluded for recently advertised jobs, including the head of the Department of the Environment, former Agriculture Minister Mrs Rodgers claimed the ban contravened the spirit of the Belfast Agreement.
"I was born in Co Donegal and am an Irish citizen," the Upper Bann MLA said.
"For three years I served as a minister in the Northern Ireland Executive.
"I cannot understand how on the one hand it is possible for me to serve as a minister but I could not apply to work as a senior civil servant for a minister.
"This is a ridiculous state of affairs and runs entirely contrary to the guarantees of equality and parity of esteem in the Good Friday Agreement."
Former Finance and Personnel Minister Mr Farren, who was born in Dublin, noted Catholics and women were "seriously under-represented" in the civil service.
Mr Farren said during his term of office he set up the review of the senior civil service which recommended an end to the ban on applicants from the Republic.
The North Antrim MLA explained: "I couldn't change this prohibition myself as its the responsibility of the Westminster government, but I was able to and did challenge its legality.
"I sought an opinion from the civil service's own legal advisers. It umabiguously concluded that the prohibition of Southerners was illegal.
"I want to know why the civil service is taking advantage of the suspension of devolution and ignoring its own legal advice. I also want to know why I am good enough to be a minister but not a senior civil servant."
Mrs Rodgers also demanded tonight that in addition to dropping the ban, the competition for post of permanent secretary in the Department of the Environment be re-run to allow applications from the Irish Republic.
PA