Crieff Hydro hopes to create 200 holiday lodges, a 200-bed care home and assisted living centre, new leisure facilities and a number of retail outlets.
Hotel bosses claim the project will eventually attract one million visitors a year, creating a massive boost to the economy from increased tourism to the resort and local area.
The development, which is now the subject of a new planning application to Perth and Kinross Council, will be phased over a 20-year period.
Those behind the project say it could result in the creation of around 125 construction jobs per year during phase one, 65 construction jobs per year during the remaining development period and up to 300 new hospitality jobs once it is complete.
Stephen Leckie, chief executive of the resort, said: "We're absolutely delighted to have arrived at such an important milestone in the planning process following an extensive collaborate and comment consultation exercise to engage the local community and key stakeholders in developing these plans.
"Feedback from the consultation process was extremely positive, with 62% of respondents supporting the expansion of Crieff Hydro Estate and 68% supporting the long-term expansion of Crieff as a tourist destination."
He added: "We will continue to engage locally throughout the planning process.
"This will give the community and businesses an important role to play in developing their community as one of Scotland's leading tourist destinations with a thriving economy, building an exciting future for all in the Strathearn area."
The firm says the project will transform Crieff Hydro into a world-class destination and a leading leisure and conference resort.
It says it will enhance opportunities for local firms in the Strathearn area and create increased footfall and spending in shops, restaurants, cafes, services and tourist attractions from both guests and staff.
The hotel's planning application relates to a 100-bed care home, 100 unit assisted living accommodation, 200 holiday lodges, up to 1000 sq m of retail space and 2000 sq m of leisure facilities including a swimming pool and gymnasium.
Mr Leckie, who is the fifth generation of his family to run Crieff Hydro since the doors opened in 1868, has previously claimed the project will be comparable to Donald Trump's north-east golf development.
He said: "This will be a £100m expense and is a big development, something akin to the Trump golf course in Aberdeenshire."