Owners of the 132-year-old Clontarf baths, recently refurbished at a cost of €2.4 million, could be breaking the conditions of their planning permission by failing to open the outdoor seawater pool at the site.

Publican and hotelier David Cullen two weeks ago opened a 250-seat restaurant and bar at the Clontarf seafront site following a two year construction and renovation programme that included the restoration of the open air seawater baths.

However the baths, which closed more than 20 years ago have not been reopened for use, and Dublin City Council is investigating whether Mr Cullen may be in breach of his planning permission for failing to open the pool, while running his restaurant.

A spokeswoman for the council said it had received complaints in relation to a possible breach of the planning permission and was investigating whether the facility was now an “unauthorised development”. Planning enforcement officers visited the site last week. If the facility is found to be unauthorised, the council could order the restaurant’s closure, pending the opening of the baths.

The Cullen family, whose business interests also include Seafield Hotel & Spa Resort in Co Wexford and the Turk’s Head and Paramount Hotel, in Dublin’s Temple Bar, bought the derelict baths in 1997.

Initially they planned to redevelop the baths as part of an indoor pool complex, but were pipped to the post by the opening of a 50-metre pool at the nearby Westwood leisure centre in Fairview.

A number of applications were made between 2000 and 2004 to turn the baths into a restaurant, craft centre and art gallery, which would have involved the permanent closure and filling in of the pool, but these were refused permission.

In 2012, permission was granted for the current development, on condition the restaurant “remains subsidiary to the main use of the site for swimming” and “shall be operated in conjunction with the swimming pool”.

Rita Barcoe, operations director of the facility said it had not yet been possible to secure insurance for the pool. “We have gone out to the market, but it hasn’t gone as we hoped and we have yet to get an insurance quote.”

She said she hoped the pool would be open to sports clubs by the end of April, but said a decision had yet to made on when it would open to the public. Keeping the pool open five days a week during the summer, and at weekends in the spring and autumn, would cost an estimated €400,000 a year she said, which would be difficult to fund through public swimming charges.

“We never expected the pool to make money, but we do need it to pay for itself. Ultimately the only reason there is now a pool in Clontarf is that there is a restaurant here, but we do hope to have them both open.”

Deirdre Nichol, of the Clontarf Residents Association said she was “concerned the pool would be opened as was intended in the planning permission”.