The Irish Medical Organisation says it will have no option but to call for industrial action by junior doctors if pay cuts being proposed by the HSE are implemented.
In a circular to junior doctors, seen by RTÉ News, the union says the HSE plans to introduce a 'devastating attack' on doctors' pay from 18 February.
This would include a mandatory one-hour unpaid meal break, cuts in overtime and a range of allowances.
Junior doctors who attend hospital courses or lectures will no longer be paid for this time, if the doctor is not available to the employer.
The IMO is to hold an emergency national meeting of its junior doctor members on 11 February in Dublin to discuss the issue.
It says that the cuts proposed are on top of the new pension levy, which itself will result in a deduction of between 6.4% and 8.5% from junior doctors' salaries.
In a letter to the IMO, the HSE says the measures are required in the challenging economic environment.
The HSE also says that the large increase in junior doctor numbers from 2,582 to over 4,600 since 1996, further supports the introduction of the cuts.