While Theunis lives in his native Netherlands he has owned a second home just south of Mönsterås for the past 30 years and has now decided to respond to a call from Kalmar county to boost larger scale tourism in the area.
"I was travelling with my wife and we saw that the sign for Oskarshamn has a witch on it, so we thought to ourselves - they have the answer right here. Perhaps you could say that when you live in the forest, you can't see the wood for the trees," Theunis told The Local on Wednesday.
The idea developed into a full-scale themed park featuring witches, trolls and all the secrets of the deep, dark forests, and has been given the name "WitchWorld".
Theunis points out that Kalmar county has only two other nearby theme parks (Öland zoo and Astrid Lindgren's World in Vimmerby) and believes that the new park is just what the area needs to capitalize on the almost 3 million tourists that flow through each year.
"Holland has 35 parks of this kind," he pointed out.
Theunis was coy when asked about how close his group is to securing the 500 million ($64 million)-600 million kronor financing required for the completion of the project.
"I have a network of around 70 people from Holland involved in the project. We are talking to investors and are confident of starting construction in the spring of 2011," he said.
The ambitious project has received the backing of the municipality with commissioner Roland Åkesson calling the plan "an ambitious and interesting project".
"I can confirm that writer and businessman Ton Theunis is planning to establish a theme park by the E22 in Mönsterås. With the correct planning and financing the theme park could become an enormous attraction internationally and have positive effects for Mönsterås," Åkesson told The Local on Wednesday.
The municipality and the group led by Ton Theunis have signed a letter of intent to "continue to work towards the realization of the project".
"The municipality's commitment extends to the physical planning, solving land issues and so on and generally assisting with various business generating activities. We are not putting up any money," Åkesson said.
Mönsterås municipality has invited local residents to a meeting on Wednesday evening to meet Theunis and discuss the impact that the new theme park will have on the area.
While Åkesson argued that the witches theme had no particular link to Småland and should be regarded as primarily a sound business proposition, Theunis begged to differ.
"There is a cultural link to Småland. The region is known, at least internationally, for its deep forests, witches and trolls are a part of that," he said.
Among the outline plans for the 70 hectare site by the E22 motorway are a 200 room hotel, parking for 1,500 cars, a man-made lake stretching 10,000 square metres, and two restaurants.
If all proceeds according to schedule then the project will begin construction during 2011 with the park set to open in 2014. The organizers hope that 400,000 visitors will visit during the inaugural year and create an initial 280 full and seasonal jobs.
Ton Theunis, formerly an employee of the district court in Amsterdam, turned his hand to writing with the publication of his first crime novel "The Tower" in 1992, the first of seven novels. Despite being a popular writer in his homeland, there are however no plans to incorporate his books into the park's theme.
"No, I write crime thrillers, there are no witches in my books. But one of my books does feature a ferry from Kiel to Gothenburg though so perhaps the park will help me to get a Swedish publisher for that," he joked.