Management and unions at Nestlé Ireland are divided on whether pickets placed on its Tallaght plant - to be sold today to a fourman consortium - are legal or illegal.

Under the Industrial Relations Act, 1990, unions must give seven days' notice of strike action.

But in this case SIPTU insists the action is official due to special circumstances surrounding the dispute.

"Our legal advice is that we are within the law," said Mr Brendan Carr, assistant secretary of the union's Dublin Food branch.

With Nestlé due to complete the sale to a management team today, it would have been too late to serve formal strike on Thursday, when talks at the Labour Relations Commission failed.

They would have welcomed a full Labour Court hearing on the outstanding issues, but did not "have the luxury of time", he said.

The Tallaght plant along with leading brands such as Chef sauce, Fruitfield jam and sweets such as Silvermint, Double Centre, Scots Clan and Yorkshire Toffee, have been sold to the consortium, Fruitfield Foods, for €20-€25 million.

Fruitfield managing director Mr Michael Carey assured the staff there would be no job losses due to the buy-out.

But the 140 workers at the plant had been seeking guarantees about their future from the outgoing Nestlé management before the sale was completed.

The union's perception is that Nestlé, a leading multinational, should give such a guarantee given work practice changes and redundancies, which made the plant an attractive takeover proposition.

Nestlé management informed the union at the LRC talks that the company was satisfied it had completed all its legal obligations and confirmed the sale would go ahead today.

A spokesman for the company said: "Nestlé Ireland will not enter into any talks until the illegal pickets are lifted and employees agree to return to work."