More resources are being called in to help search for the missing trampers in Tasman

It's been nearly two weeks since Jessica O'Connor and Dion Reynolds set off for a hike in the Kahurangi National Park.

Police say no heat or light sources were found by an Air Force helicopter that searched inland from the Anatori River mouth overnight.

The number of searchers involved is now expected to grow throughout the day, with drones also searching for heat and light.

Police have yet to confirm if either the footprints or a historic campsite located yesterday belong to the pair.