Two walkers have been rescued after becoming disorientated in dense rhododendron in Killarney National Park.

A rescue operation coordinated by Valentia Coastguard was launched to locate the pair who had camped overnight near Killarney's largest lake.

Three rescue teams including the Shannon-based Sikorsky rescue helicopter, Kerry Mountain Rescue and Killarney Water Rescue were deployed.

The rhododendron is jungle-like along the western shore of Lough Leane lake where the rescue operation took place.

The tourists had camped near Glena Cottage overnight, around 400m into the shelter of the dense rhododendron.

However, they became disorientated and could not make their way out of the forest this morning.

They managed to get a phone signal and contacted Kerry Mountain Rescue at around 2pm.

Rescue 115 used thermal imaging to locate them but could not get a winch down to them because of the dense overhang of the rhododendron in the area.

Instead they were guided to the lake shore where a local boatman picked them up.

It is not the first time walkers have become lost in rhododendron in Killarney - last year Kerry Mountain Rescue managed to pluck a walker off nearby Shehy Mountain.

Rhododendron ponticum is a problem in the park and around €200,000 was spent by the Department of Arts, Heritage and the Gaeltacht in trying to contain its spread.

In the past around 3,000 of the more than 10,000 hectares were affected to some extent but significant inroads into the problem has been made and 2,000 of the 3,000 hectares, involving 40 different sites, have been brought control.

Teagasc released figures today stating annual cost to Ireland of invasive and non-native species is estimated at €261 million.