The project is so large that it would tilt Phuket's demographic balance and speed the northward growth of an island rapidly becoming ''Phuket City.''
Last night at the party, Laguna Phuket founder KP Ho revealed that the plan includes a large scale tourism attraction which will be anchored as an international standard water park.
Phuketwan first reported the new project in a farewell interview with long-time Laguna Phuket Chief Executive Michael Ayling, whose replacement has yet to be announced.
Here's what the birthday anniversary media release has to say:
Launched in 1987 when its first hotel opened for business, Laguna Phuket today celebrates a quarter century of achievement that has seen it evolve into Asia's finest destination resort, with a unique and internationally-recognised ''Laguna Lifestyle'' enjoyed by guests and residents alike.
During the past 25 years, its 1000 acre site on Phuket's north-west coast, originally a desolate wasteland scarred by tin mining, has been transformed into a lush tropical lagoon-filled integrated complex of luxury hotels and residential villa properties - complete with exceptional restaurants, world-class spas and a renowned golf course - that continues to set benchmarks of excellence.
In addition to attracting millions of guests from around the world to help put Phuket on the international tourism map, Laguna has also created thousands of local jobs to become the island's leading employer.
It is a prominent contributor to local communities and charities through an array of Corporate Social Responsibility (CSR) programs and has become the regional venue of choice for high-profile international sports events.
And over the years, Laguna's development of high quality hotel properties, residences and facilities to anticipate and meet changing demands has garnered numerous international awards.
This philosophy of continual enhancement is being maintained with the unveiling of a design concept for future development featuring a new hotel, condominium, commercial and leisure complex at the heart of the resort.
''Today we celebrate our past achievement in launching Asia's first integrated destination resort that created the Laguna Lifestyle, but we also look to the future with confidence as we map out a new role for Laguna Phuket to support evolving tourism demands of both Phuket and Thailand,'' said Ho KwonPing, chief executive officer of Laguna Resorts & Hotels.
''We are extremely proud of what we have created here and the international stature we have achieved as a holiday destination, property hotspot, international sports venue, focus of CSR activities, and even a setting for memorable marriages at our unique waterside Wedding Chapel, one of our many diverse resort attractions.
''Today I particularly want to pay tribute to our many long-serving local staff throughout the resort who have devoted years of dedicated service to help the company fulfill its aims. I am confident their dedication will continue to support our new initiatives in the years to come.
''As our international source markets and the demands of holidaymakers and residents inevitably change, we must anticipate these shifts and adjust our offerings to remain relevant, maintain our focus and consolidate our industry-leading position,'' he said.
The new design concept is for an integrated development on a parcel of land overlooking one of Laguna Phuket's west-facing beachfront lagoons, between the Laguna Beach Resort and Dusit Thani Laguna Phuket.
The concept is for an integrated complex of buildings among a series of waterways with a hotel, luxury condominiums, Water Park, and space for up to 1000 shops and restaurants.
Laguna Phuket's international appeal is spread across a wide variety of visitor categories as well as those who simply want a holiday in an idyllic Thai location.
The iconic Laguna Phuket Triathlon, now in its 18th year, and the more recently-introduced 70.3 Ironman triathlon, attract triathlon devotees in the thousands from across the globe.
The Laguna Phuket International Marathon is also a popular draw for thousands of novice and experienced runners of all ages and nationalities.
In April and May of this year, the resort's MICE (Meetings, Incentives, Conferences & Exhibitions) credentials were taken to a new level when Phuket's largest corporate gathering, an Amway China leadership seminar involving 15,000 delegates in a month-long rolling program of activities, was hosted on property.
Laguna Phuket is the island's most respected property developer with a portfolio of luxury apartments, townhomes and villas set in beautiful locations around the resort that have drawn consistent worldwide interest from buyers seeking the Laguna Lifestyle.
The picturesque Wedding Chapel, overlooking a tropical lagoon, has hosted hundreds of marriage ceremonies for couples seeking a wedding to remember.
Laguna Phuket Golf Club, host of the 2009 Thailand Open, is consistently popular with local and international golfers, and the resort's five spas are renowned for their world-class treatments.
In addition to the on-going CSR fundraising activities, which in recent years have rebuilt flood-damaged local schools and taught thousands of local schoolchildren vital swimming skills, Laguna Phuket runs a Kindergarten School for children of employees, a local language school set up as part of its post-tsunami aid program in 2005, the Banyan Tree Training Academy for staff, and cooperates extensively with local government and authorities to organise annual community-wide events.
Local conservation initiatives include an annual sea turtle release and planting of thousands of mangrove trees with local authorities to reclaim threatened local swamplands.
Laguna Phuket's success is also being exported internationally with the launch of Laguna Lang Co, currently under construction in central Vietnam.
This new seafront development, scheduled to open in November 2012, is based on the Laguna Phuket concept with Banyan Tree and Angsana properties, as well as spas and an international standard golf course.