The head of the Irish Nurses and Midwives Organisation (INMO) has said the regulator needs to sit down and pay "respect" to its members over an increase in its registration fee.
It comes after the Nursing and Midwifery Board of Ireland (NMBI) has said the fee for 2015, due on January 1st, must be €150.
That is €50 more than the current fee.
The Irish Nurses and Midwives Organisation says the increase in registration fees for 2015 is unreasonable.
The NMBI says that "the board has to be self-funding, which means that registration fees for 2015, due on January 1st, must remain €150."
"For unions to advise otherwise to registrants is misleading," it says.
"Employers including the HSE have confirmed to the Board that they cannot employ nurses and midwives who have been removed from the register."
"Full payment of the ARF is required for registrants to attain a valid Certificate from NMBI and be on the register. It is illegal to practise if removed from the Register for non-payment of the Annual Retention Fee," it adds.
But INMO chief, Liam Doran, says the increase for his members is simply not fair.
He told Newstalk Lunchtime that there was no consultation with members over the change.