Minister for Employment Affairs and Social Protection Regina Doherty has said nurses have not said they are not happy with their pay.
Speaking on RTÉ’s The Week in Politics, Ms Doherty said the nationwide 24-hour strikes were announced "on the basis that they are not happy with retention, they haven't said they are not happy with their pay".
If the dispute is not resolved, there will be further 24-hour strikes on 5 and 7 February, and then on the 12, 13 and 14 February.
Fianna Fáil's Stephen Donnelly said: "Nurses are the lowest paid graduates in our health service, they are asking why a physiotherapist with the same level of education is getting €6,000 more than them."
Sinn Féin's Martin Kenny said: "The reality is the nurses are looking for more pay...we need to stop giving tax breaks to bankers and large corporations and start funding our public service."
Minister Doherty said new entrants will see their salary increase by €3,000 this year.
A spokesperson for the Irish Nurses and Midwives Organisation has said pay is the solution to the nurses dispute.
The INMO was responding to comments made by Ms Doherty.
A spokesperson for the INMO said: "Pay is not the cause of this strike, but it is the solution. With fair pay, the HSE will be able to recruit and retain enough nurses and midwives for a safe health service."
"The main cause of this dispute is under-staffing. The HSE simply cannot hire enough nurses and midwives on these wages.
"Ireland's nurses are increasingly looking overseas, where they have better pay and conditions, and are on equal wages to their physio and therapist colleagues.
"In Ireland nurses and midwives face a €7,000 salary gap with their graduate colleagues, at every point on the scale," added the spokesperson.