Hawaii locals have been left furious after developers allegedly began unauthorized construction for a massive zipline through their idyllic mountainside.

Residents of Laie on Oahu’s northeast shore have long opposed the plans for the attraction over fears it could overcrowd the area with noisy tourists.

The zipline was first proposed by operator Climb Works in 2020 and could bring more than 1,000 visitors to the area each day.

As well as angry locals, the US Army also raised concerns the height of a zipline tower could disrupt planes overhead.

However, the feud reached new heights this week after it emerged that construction for the project was forging ahead and a local hiking route had been blocked as a result.

Recently surfaced photos taken by local resident Timothy Strain appear to show how a hiking trail had been converted into an access road for construction vehicles.

City of Honolulu officials have since told SF Gate that the works were unauthorized.

‘No building permits have been granted, and site development has not been approved,’ Davis Pitner, a spokesperson for the Department of Planning and Permitting, said.

Locals on a Hawaii mountain have been left furious after developers allegedly began unauthorized construction for a massive zipline through their idyllic valley 

Laie residents have pushed back against developer Climb Works since the project began in 2020. Local Timothy Strain claimed that the construction has blocked off a hiking trail

The City and County of Honolulu’s Department of Planning and Permitting told the SFGATE the work had not been approved

The department said it reviewed the photos and identified apparent ‘grading and building violations.’ 

Climb Works leases 464 acres for the project from Property Reserve, a real estate company affiliated with The Church of Jesus Christ of Latter-day Saints.

Property Reserve owns more than 6,000 acres of land in Hawaii, much of it in Laie.

Asked about the project’s approval status, Aaron Campbell, a partner with Climb Works Adventure Co. Laie, told SF Gate: ‘We’re happy to continue working with the department on any questions they may have, as we’ve done throughout the project.’

‘We’re committed to following the applicable permit requirements and working cooperatively with the appropriate agencies.

‘We know there are people in the community who have different views about the project, and we respect that. Our goal has always been to move forward thoughtfully and responsibly while caring for this land for the long term.’

One of those residents, Kamalani Keliikuli, who previously challenged the development, said she was devastated by the recent photos.

‘It’s heartbreaking, honestly,’ Keliikuli said. ‘It just, you know, it didn’t give us enough time to even hear about what was going on.’

Climb Works did not directly answer if photos of recent construction were approved but told the outlet: ‘We’re committed to following the applicable permit requirements and working cooperatively with the appropriate agencies’ (Climb Works founder Nick Thompson pictured) 

The zipline has been opposed by locals and the US Army which raised safety concerns that the height of a zipline tower could disrupt planes overhead

‘Everything just kind of happens last minute and seems like we’re kind of late in the process of trying to make a change, which has been heartbreaking for us as a community.

Campbell’s claim that the company is following permit requirements was challenged by the planning department, which said key conditions have not been met.

In 2020, Climb Works received a conditional use permit for the project that required at least 50 percent of the property to be in active agricultural use before certain development could proceed, according to the department.

‘Agricultural activities such as goat and sheep ranching, crop production, and forestry do not require a CUP [Conditional Use Permit] or MOD [modification to an existing CUP],’ Pitner told SFGATE.

‘However, construction of agribusiness-related structures is not currently allowed because the property has not yet met the CUP conditions.’

Honolulu officials are preparing a notice of violation for Climb Works.

‘In this case, the property owner will have to obtain a building permit to correct the building violation or remove the unpermitted structure,’ the department said.

Officials added that permit fees would be tripled because the work was performed without approval.

The Daily Mail has contacted Climb Works and the City of Honolulu for comment.