Stocks of chilled food to Tesco may be affected over the coming days due to threatened industrial action at supermarket suppliers Keelings Distributions.
Keelings Distribution is part of the Keelings Logistic Solution Group which, in conjunction with Tesco Ireland, manages the largest temperature controlled food retail distribution centre in the country.
Keelings employs up to 400 people at its plant in Ballymun, Dublin.
Siptu is balloting for industrial action at the company due to what it says is management's "arbitrary breaches of policies, procedures and agreements."
"Keeling's management is in breach of its agreement with SIPTU on a range of issues including the ratio of contract employees to full time employees and absenteeism policy," Siptu branch organiser Pat Ward said.
Mr Ward said the union had made every effort to resolve the issues in dispute but now felt it had no alternative but to begin balloting for industrial action.
The ballot is due to start today and will conclude on Friday. If strike action is decided upon, supplies of chilled foods to Tesco may be affected, he added.