Contractors working on the Promenade reconstruction project have found further cracks in the concrete.

Cracking in the newly laid coloured concrete in the rail corridor was first spotted last month as highway chiefs admitted the scheme was now 10 weeks behind schedule.

A new method of construction was introduced which involved laying a steel mesh before the cement was poured.

But now further cracks have appeared on Central Promenade in a 200m section where the mesh was laid.

A full investigation is under way.

The government posted on its Facebook page: ’Auldyn Construction has reported further cracking in the red concrete that is being used between the rail tracks on Central Promenade.

’The red concrete laid alongside the rails in this section of the Promenade doesn’t appear to be showing any cracks but is being monitored carefully.

’A full investigation is under way in order to assess what has caused this new cracking and how this can be fixed.’

A spokesman for the Department of Infrastructure said: ’It will need to be repaired but first of all we need to understand what is causing the concrete to crack.

’We are investigating the cause of the cracking with experts.’

Asked why red asphalt could not be used instead, she replied: ’The concrete has been part of the design for some time and to change now could add further time and cost.’

Responding to a Freedom of Information inquiry, the DoI said liability for the costs would be determined once the investigation into the cause had been concluded.

The department said: ’Any costs deriving from remedial action will be dealt with in accordance with the provisions of the contract.’

Meanwhile, the horse tram service has been extended south and now stops at the Palace Hotel.

The first trip down to the new terminus was pulled by tram horse Rocky.