A $1 million zipline course is taking shape on the Illawarra escarpment as tourism behemoth Merlin Entertainments Group takes off on a dramatic expansion of the Illawarra Fly Treetop Adventures site.
The course will consist of two suspended bridges and three ziplines - flying fox-style cables that tourists slide along using a suspended harness.
The lines are stretched between trees up to 35 metres off the ground and have been placed so visitors will "fly" over pedestrians on the treetop walk below.
At the Knights Hill site on Wednesday, workers prepared to secure one of four galvanised steel "cloud stations" to supporting trees.
The stations clamp around the metre-thick trunks like halos, and will serve as take-off and landing stations between the course elements, with room for 12 people.
Site general manager Neredith Elliott said the attraction was intended as the first in a series of add-on experiences at the rainforested site, giving visitors more to do and increasing the likelihood of repeat business.
About 50 per cent of visitors to the Knights Hill rainforest are from Sydney, with weekenders in their 20s and 30s a well-represented demographic.
"One of the key drivers is to increase the [stay] time of guests so their experience is larger, longer, with more things to do," Mrs Elliott said.
"We want to make that travel, particularly from Sydney, worthwhile."
Current operations only use about 10 per cent of the 18-hectare site.
Mrs Elliott said future plans included attractions for children and facilities for overnight stays.
"Glamping" - glamorous camping - is on the cards.
"What we're really wanting to do long term is place this as a destination," Mrs Elliott said.
"This is really just stage one."
The zipline course was set out according to the location of suitable trees, which have been examined for signs of rot or ill health.
Australian-based zipline and canopy course specialists TouchCloud Global prefabricated the components in Mona Vale before delivering them to the site without the use of heavy machinery, in line with the operation's environmental ethos.
Installation is expected to take five weeks and conclude by December 20.
Tours will cost $75 for adults and $45 for children, with the treetop walk included.
They will take one to 1½ hours and be led by guides who will speak about the area's environmental credentials, with the focus on "medium adrenaline" eco-tourism, rather than thrills.
UK-based Merlin Entertainments Group owns Madame Tussauds and is the world's second-largest tourism operator, after Disney.
The expansion will create 10 part-time and seasonal jobs - almost double the current staff.