Due to the flow of water, a tunnel has been formed below Makutta highway.
The location is about one kilometre away from Perumbadi check-post. The incident came to notice recently.
According to the experts, the tunnel may be about six feet wide and around 30 foot long. It might have been formed as a result of water flow during heavy rain in the monsoon. The water might have flown down the hills, from the border regions.
However, the tunnel has not affected the movement of inter-state vehicles on the road, which connects Kerala with Karnataka, through Kodagu.
PWD Virajpet division assistant executive engineer Suresh said that the incident came to the notice of the department 30 days ago. A spot inspection was conducted by technical experts.
There is a need for a minor bridge in the area, for the protection of the state highway, he said.
A proposal has been submitted to the government on the construction of a bridge at a cost of Rs 25 lakh. Work will commence shortly after obtaining approval from the government, he added.