Work to complete the $500,000 toilet block at the Waipa mountain bike carpark should be finished by mid-March.
Rotorua-based Burton Construction foreman Robert Burton said work was progressing well and should be finished about two weeks ahead of schedule.
The new toilet complex would cost about $495,000 and includes four showers and changing rooms, as well as 12 new toilets.
The complex will be completely covered with dirt and will feature an overhead cycle bridge, providing a gateway into the Whakarewarewa Forest, and a central cycleway through the middle of the complex.
The much-needed facilities will provide high-quality facilities for the National Mountain Biking Centre of Excellence, which will be based in Rotorua.
Rotorua District Council parks and recreation manager Garry Page earlier said toilet facilities at the mountain bike carpark were basic portaloos.
A composting toilet donated by the Rotorua Mountain Bike Club and Fletcher Challenge Forests was destroyed by arson.
Mr Page said art features relating to forest activities would be incorporated into the building.
The Waipa carpark toilet block was designed by architect Andrew Byder, who also designed Red Stag Timber's mountain bike hotel which is to be built on adjacent land.
Mr Burton said it had been a stop-start job due to the materials used.
"With the concrete building, it's been on and off due to waiting for the concrete to settle before moving on to the next stage," he said.
"It's an interesting job because when it's done it's going to be completely covered."