A historic railway tunnel that forms part of the Taumarere - Opua leg of Pou Herenga Tai/Twin Coast Cycle Trail has been closed over fears it could partly collapse.

The Far North District Council has closed the tunnel, which means those using that leg of the cycle trail will have to follow a track over the small hill the tunnel goes through. There's no date for when the tunnel can be repaired and deemed safe for public use.

Andy Finch, council's infrastructure and asset management general manager, said there is a crack in the arch of the tunnel at the Opua end.

''The crack is near the crown of the tunnel and it could develop if additional weight is applied from above. It is possible that masonry could dislodge and fall into the tunnel.

Advertisement

"The FNDC has received advice that this is a significant health and safety risk along with a recommendation to close the tunnel pending repairs.''

Mr Finch said the council cannot say at this stage how long the tunnel will be closed.

The council leases this section of the cycleway from the Bay of Islands Vintage Railway Trust and will need to discuss repair options with the trust before any decision is made.

Mr Finch said a health and safety report was ordered by the council in September as part of routine inspection programme of both cycle trail tunnels (Opua – Kawakawa and Okaihau – Kaikohe).

The resulting inspection identified the cracks and the risk of failure.

''Gates are being erected today to block access at either end of the tunnel. A detour over the top of the tunnel will be used during this time. Detour signs will also be erected at both ends of the tunnel and at the Opua and Kawakawa ends of the cycle trail,'' he said.

''The Opua – Kawakawa section of the Twin Coast Cycle Trail remains open and we hope users will continue to enjoy this great facility.''

To mitigate risk going forward there will also be a "trail alert" on the home page of the cycle trail website.