The lifestyle group behind some of the hottest local nightclubs in recent years such as Mink, Filter and Suite 26 appears to have vanished, just two years after the launch of its ambitious South Beach Quarter project.

Checks by The Straits Times found that Massive Collective's website, contact number and e-mail address have gone offline as it battles financial and legal woes, including lawsuits from two of its co-founders.

Started as a lifestyle marketing and management agency in 2009 by party promoters John Langan, Phillip Poon, Cedric Chong and John Bosco Lopez, Massive Collective grew to become one of the biggest nightlife operators in town through a series of joint ventures, starting with the members-only nightclub Filter at Gallery Hotel.

Opened in 2010, the club popularised the "bottle popping" culture, in which clubbers showed off their wealth by lavishing thousands on premium bottles of champagne.

This was followed by upscale nightspots such as Royal Room and Mink at Pan Pacific Singapore. All three closed after three years to make way for new concepts.

Massive Collective took over a 13,000 sq ft two-storey building in South Beach, a mixed-development project in Beach Road, in 2015 with four food and beverage concepts: Vatos Urban Tacos, a Korean-Mexican restaurant chain from South Korea; gastropub The Armoury; cocktail bar Vanity; and the exclusive nightclub, Suite 26.

Suite 26 and Vanity, later rebranded as nightclub Penthouse, both closed earlier this year, while staff at The Armoury told The Straits Times on Monday that they are no longer managed by Massive Collective.

Vatos co-founder Sid Kim said that while the business was brought to Singapore as a joint venture with Massive Collective, the latter was never involved in its operations.

A joint venture contract with The Prive Group for nightclub Bang Bang also expired last year, according to Prive Group chairman Yuan Oeij.

Documents obtained by ST show Massive Collective was evicted from its Midland House office in April for failing to pay rent arrears.

Its current registered address is Naughty Nuri's restaurant at Capitol Piazza, another of the firm's joint ventures, though it is not clear if the company is involved in the restaurant's operations.

Mr Poon told ST that he left Massive Collective in January after its current director, Mr Huang Sijin, bought over Mr Chong's share last year and they failed to see eye to eye on how to run things.

Mr Poon sued Massive Collective for unpaid salary and other claims, and obtained a High Court judgment in his favour in July. "It is unfortunate that it's gone the way it's gone," said Mr Poon, who has since started an F&B management and investment firm with Mr Lopez.

Mr Langan said he left the firm in the middle of last year "due to legal issues which are still before the courts". He added: "I am very proud that Massive Collective helped to engineer some of the region's most unforgettable nightlife experiences, and a community of friendships that I will cherish for a lifetime."

His lawyer Jonathan Yuen, a partner at Rajah & Tann, said Mr Langan successfully obtained several orders from the High Court against Massive Collective and Mr Huang earlier this year.

Mr Huang, known to associates as Vallence, declined to comment.

Singapore Nightlife Business Association president Dennis Foo said that Massive Collective catered to the high end and "took the dance club market by storm".

But with operating costs in the industry continuing to rise, "niche market segments cannot sustain too many larger-scale venues, especially in these challenging times", said Mr Foo.

Correction note: This article has been edited for clarity.