Row over 'political' role of civil servants
The roles of two leading trade unionists - who are also members of the Socialist Party - in the civil service has been criticised.
Nipsa president Carmel Gates and Patrick Mulholland - who is running to be the next general secretary - have said they are proud members of the Socialist Party.
Ms Gates is also a civil servant, but businessman and right wing commentator Jeff Peel questioned her activism, saying that as a civil servant she should not be political.
The row between the pair was broadcast on the Nolan Show.
Mr Peel asked Ms Gates to confirm whether she is a member of the Socialist Party, to which she replied: "Of course I am. It's no secret - all my members know that.
"I am a proud member of the Socialist Party and my colleague Patrick Mulholland who is running for general secretary, is a proud member of the Socialist Party."
Mr Peel went on to ask whether being a member of a far left group that used to have a militant faction was appropriate for a civil servant, who, he said, are supposed to be neutral.
"It is the basic tenet of civil service duty, that you are neutral and not political. Yet you are a member of the Socialist Party and you take a full time salary, and you dedicate all of that time to trade union work," he said.
"Is that fair to the public purse?"
Ms Gates responded: "This is becoming quite libellous, you need to be careful.
"In my role as a civil servant, I act as a civil servant and do not act in a political role. In my role as president of Nipsa I am free to espouse my politics. There is a clear distinction."
It emerged yesterday that the taxpayer is funding the wages of public sector staff who work on trade union business to the tune of £5m a year in Northern Ireland.
This has been defended by Mr Mulholland who is in the running alongside Alison Millar to replace Brian Campfield, who is currently head of Nipsa.
The chief of Nipsa, which represents more than 45,000 workers, is due to retire in January 2016.
The election to find his successor is due to take place next month with nominations being sought from candidates this month.