Work will begin within days on the £110m Bluestone leisure village which could create 900 jobs in Pembrokeshire.
The village is designed for the "more discerning visitor"
The project, delayed by long legal battles, will receive a £14.5m grant from the assembly government and another £4m from Finance Wales.
The first phase - including 235 log cabins and a water park - will open in June 2008.
But a Friends of the Earth spokeswoman said tourism in the county should focus on the area's unspoilt coastline.
Rebecca Cadbury, who lives in Narberth close to where the Bluestone village will be built, said taxpayers' money should not be used for developments like this.
"Pembrokeshire's main attractions are its unspoilt countryside, small rural towns and its magnificent coast. I feel that what we need to see is tourist development that takes advantage of these," she said.
"Jobs have been used as a justification and there will be jobs - the problem is the nature of those jobs.
"They are likely to be seasonal [and] they are going to be poorly-paid jobs in the main."
But Bluestone chief executive William McNamara said the company was creating a "year-round attraction", so the work would not be seasonal.
"We have had an enormous positive response to the Bluestone job opportunities," he said.
"These are year-round jobs with progression and development opportunities including graduate placements to bring some very serious opportunities to local people."
Mr McNamara told BBC Wales construction would begin "in a matter of days" and said the company did not take lightly the responsibility of building within the Pembrokeshire Coast National Park.
"We didn't 'get over' the rules - we abided by the rules. We have been through a completely democratic process through planning that was successful."
Bluestone hopes the holiday village - catering for the "more discerning visitor" will bring in up to 100,000 staying visitors a year.
The water park is in the first phase of the development
It said the project will provide a completely different experience from anything else in the UK.
Two all-weather attractions - a sub-tropical waterworld and snow centre - are also projected to bring another 250,000 day visitors each year.
Enterprise Minister Andrew Davies praised the project as "the ultimate indigenous sustainable business".
Signing the funding agreement with Bluestone, the minister added: "The concept was conceived in Wales, it will be developed in Wales, delivered by Welsh people, provide jobs for local people, benefit Welsh businesses, and promote our distinct Welsh culture and heritage internationally."
Other financial backers include Mansford Holdings PLC and Bank of Scotland Corporate, while Pembrokeshire Council is providing a loan.
The holiday village received clearance from the House of Lords a year ago after opposition to the scheme by the Council for National Parks (CNP) was finally rejected.
Part of Bluestone will be built in the Pembrokeshire Coast National Park and the CNP had claimed this would establish a precedent which could allow development on other UK protected parkland.
Work on the snow centre and second phase of the development is scheduled for 2009.