The Dunedin City Council has granted non-notified resource consent for the event, which will be held in a fenced, licensed and security-controlled area centred on a large sea cave at the beach.
Organisers will have to comply with 45 conditions and "advice notes" designed to protect the area's sensitive dunes, plants, wildlife and residents from disruption, while keeping dancers safe from any possibility of rockfalls inside the cave.
The Cave Sessions 2010 party is scheduled to begin at 3pm next Friday, featuring New Zealand and Dunedin dub/roots acts. Patrons are expected to clear the site by 2am.
Alcohol is to be sold during the event, and sound and lighting equipment, generators and other facilities installed from two days before the event.
Rave organiser David Booth, of Emberley New Zealand, said when contacted he was "relieved" the council had decided to grant consent, and confident the conditions - many of which he suggested - would work.
"Most of those conditions were ones we proposed, in terms of security and [site] layout and the like.
"We are very confident we can eliminate or reduce all the risks to the environment and the community," he said.
Long Beach Amenities Society spokesman Nic MacArthur said there was "bitter disappointment" within the Long Beach community at the council's decision.
"The decision was perplexing and disappointing for the local community after a packed meeting in the Long Beach Hall ... showed that a large majority did not want the event.
"Previous similar events had often trashed the cave, drunken patrons had abused local residents, and traffic noise and volume were unacceptable."
Mr MacArthur acknowledged organisers had "taken good notice" of community concerns, but remained sceptical the event's adverse effects could be controlled.
He said residents were "praying for rain" in the knowledge severe weather could see the event transferred to Dunedin nightspot Sammy's.
Mr Booth confirmed Sammy's would be used if severe weather made the beach location unsafe.
An 18-page decision by council planner Darryl Sycamore outlined the reasons for granting non-notified consent, and measures designed to protect the area.
The event would be controlled by 20 security guards, preventing revellers from spilling into other sensitive areas and monitoring their movements within the Long Beach township.
St John ambulance staff and four lifeguards would also be on site, along with a "passive" police presence.
Buses would transport revellers to and from the site, and rubbish, recycling, toilet and fresh-water facilities would be provided, along with a plan to deal with unruly patrons ejected from the site.
Efforts would be made to minimise noise and light pollution during the event, and rubbish sweeps would help restore the site to its previous condition afterwards.
A council consultant engineer had found the cave to be safe to use, while a consultant mining specialist identified one rock formation within the cave needing to be fenced, reinforced or checked for loose debris before the event.
"It cannot be guaranteed that there will not be a rockfall event at any given time, however the effect of foot traffic and amplified music at the site will not exacerbate that risk," Mr Sycamore's report said.
Mr Sycamore said visitors were a "daily occurrence" at Long Beach, including large groups - several hundred school pupils descended on the area earlier this month, and previous unsanctioned events in the cave had attracted up to 3000 revellers.
Sealions, penguins and other wildlife could be relocated if found wandering towards the cave during the rave, but Department of Conservation staff found no penguins in the cave during a visit last month.
A fence would also be installed to protect plants and a bond paid by organisers to cover the cost of any damage.
Mr MacArthur said the amenities society was worried the decision would set a precedent for other small communities, but council resource consents manager Alan Worthington said that was not the case.
The consent was for a one-off event, with no precedent set if consent for a future event was sought, he said.
The rave's organisers were the first to seek consent for an event in the area, and had been "pretty thorough" in their application, he said.
