WORK on a £60m power plant on Teesside is once again being threatened by industrial action due to an employment dispute, it emerged last night.

The Amicus union has warned that its members working on the Wilton 10 project could vote on taking action unless EI.WHS reduces the number of agency staff it has on its books.

However, the company, which is contracted by Foster Wheeler to provide electrical and instrumentation work, said it has been unable to employ direct labour despite advertising. Of the 100 workers based on site, about 60 are employed by EI.WHS, while 40 are understood to be agency staff.

Business manager Jeffrey Mulroy said all workers had been offered the chance to be employed directly by the firm.

He said: "We have advertised for direct labour, but there are a lot of people in the construction industry who don't want to work direct and go on the books. We offered all our agency workers the chance to come on the books and only three took us up on it. We ensure that all our workers get the same rate of pay, the same site allowances and expenses. It doesn't save us any money by using agency staff.

"At the end of the day, we have a job to do. We are not looking for conflict. We are more than willing to sit down with Amicus about this and ask them to show us where it states we can't use agency staff."

Amicus said there is an agreement in place to ensure the firm uses directly employed staff and has written to EI.WHS asking for a stage two meeting.

A union spokesman said: "If workers are directly employed they get all the benefits, such as sick pay and holiday.

"Using agency staff saves costs because you don't have to pay employee National Insurance contributions and holiday pay."

Amicus believes the company is in breach of the National Agreement for the Engineering Construction Industry by employing agency labour. A spokesman said: "We are taking it through the national proceedings to try to bring them to book. Trade unions certainly find it totally abhorrent. It may well lead to industrial action in the future."

Work on SembCorp's Wilton 10 project was threaten by industrial action over the summer, when some employees were involved in a pay dispute with Foster Wheeler.

The threat was lifted in July, when Foster Wheeler agreed to more than treble workers' second-tier payments.