Quick answers on the TEL bridge fire at Papamoa are unlikely, the NZTA revealed today.

Engineers have been onsite for a preliminary look at the damage following last week's blaze.

Fire damaged a key section of the TEL bridge last Thursday night. Photo: Cameron Avery.

They will start investigating the reinforcing inside the concrete over the next few days to see if it has been impacted by the heat from the fire.

'We'll know in early December more about the damage and impact on the project,” says NZ Transport Agency's Waikato/Bay of Plenty regional director Harry Wilson.

Engineers had their first look at the damage to the bridge structure yesterday, but determining the full extent of the damage from the fire in the abutment structure could take a couple of weeks.

The spectacular blaze, thought to be deliberately lit, burned into the polystyrene blocks being used as filler in the Domain Road interchange ramps.

The abutment structure is like a layered cake, using courses of large polystyrene blocks covered by steel reinforced concrete.

Over the next couple of weeks engineers are going to be testing the integrity of the steel reinforcing as well as checking for heat damage.

Until the structural tests are complete, the agency won't know the size of the repair job, whether it will be just the top layer or if more extensive work is required.

'It might be the top layer, but they haven't gone in to have a proper look and they don't want to say."

The project is currently several months ahead of schedule.