The Department of Public Expenditure is overinflating the estimated cost of giving nurses a pay rise, according to the INMO.
Nurses are calling for equal pay to other health service staff whose positions require the same level of qualification as theirs.
The Department says this would cost the exchequer an extra €300 million per year.
The INMO are to ballot for strike action next week unless the Government tables new pay proposals.
General Secretary of the INMO, Phil Ni Sheaghdha says the Department has refused to meet with them.
"We believe that that is an overinflated figure, for starters.
"We'd have to sit down with the department. We've asked to meet with them and we've given a number of different opportunities for the department to meet with us. They have chosen not to.
"We would prefer to have a dialogue with them. We have some very good ideas about how we save money in the health service."
Meanwhile, 510 patients are waiting for beds this morning in hospitals around the country, according to today’s INMO Trolley Watch.
346 are waiting in the emergency department, while 164 are in wards elsewhere in the hospital.