There's upset at plans by RTÉ to carry out a review of its National Symphony Orchestra and Concert Orchestra. SIPTU fears 31 full-time positions could be lost between the two groups by next June.
According to the RTÉ annual report for 2016, 211 people were employed in the orchestra division, which was allocated almost €12.7 million.
It's been reported that, while the musicians provide their own instruments, their salaries range from €30,000 to €75,000.
The RTE Concert Orchestra recently proved massively popular when they teamed up with Jenny Greene to perform a set full of dance music classics, similar to BBC Radio 1's Pete Tong.
SIPTU has warned that its Orchestral members are not ruling out industrial action if changes are forced through without consultation.
The trade union's Graham Macken, said "There are a number of vacancies within both orchestras that remain to be filled for quite a considerable time, at this stage."
"Our members expect these roles and any additional vacancies that may become available as a consequence of the current voluntary exit package to be advertised without delay", a statement read.
SIPTU has warned that a wrong move from RTE "could trigger a significant opposition” from its orchestras.