Former staff of Independent Newspapers have been warned they could lose financial benefits unless they sign up immediately to a new company pension plan.

Trade unions are in dispute with the group over its plan to set up a new defined-benefit pension scheme for staff that would be closed to new entrants. The National Implementation Body (NIB) is to intervene in the row, and plans exploratory talks on Friday.

The NIB is made up of senior representatives of the Government, employers body Ibec and the Irish Congress of Trade Unions. Its involvement is being seen as the first test of new procedures to deal with pensions disputes included in the social partnership programme Towards 2016.

The company currently operates a defined-benefit pension scheme, which provides a guaranteed return for members on retirement. In response to a funding deficit in the scheme, it plans to close it off to new entrants and offer future staff members a contributory pension only.

Unions at the company have voted to take industrial action if changes are made to the current pension arrangements without agreement.

In a letter to deferred members of the scheme - former employees who have not yet retired - on Friday, the company's director of human resources, Declan Carlyle, said measures were needed to restore the scheme to solvency.

He said a majority of employees had accepted the company's offer of additional funding for the scheme, in tandem with an increase in their own contributions. But he claimed a minority of staff, supported by the unions, had yet to accept the company's offer. It was "essential" that deferred members return forms confirming their acceptance of the new arrangements prior to September 14th.

But a spokesman for Independent Newspapers said tomorrow was a "target date", not a deadline.