The company behind Mystery Park, currently under construction in Interlaken, says it needs a further SFr43 million ($26 million) to complete the project.
The theme park is being built on Interlaken's former military airfield and is based on the books of best-selling Swiss author Erich von Däniken.
Management of the SFr86 million project told a news conference on Friday that they had not ruled out delaying the opening of the park - scheduled for November 7 this year - by two to three months.
However, the chairman of the board of directors, Oskar Schärz, said that the financing of building contracts already awarded was secure. Continuation of operations is also guaranteed until the end of the year.
"Liquidity is not at risk," Schärz said, adding that the realisation and anticipated revenue potential of Mystery Park were "by no means in question".
Institutional investors encouraged
The board is proposing two steps to encourage increased participation in the park by institutional investors.
One is the creation of an approved share capital of a nominal SFr10 million for the formation of a strategic alliance. This would allow the board to offer one million bearer shares for subscription to larger private investors or companies.
The second step would be a conditional increase of a nominal SFr10 million in share capital. These shares would serve to secure a convertible bond issue.
A statement said this would satisfy the requirements of institutional investors: namely higher security, a fixed interest rate and a defined duration.
Consortium or alliance
The board said both steps had been created after "intensive discussions" with institutional investors, who had shown an interest in raising the funds necessary to secure the remainder of the financing within the framework of a consortium or alliance.
To date, Mystery Park has raised SFr36.6 million in equity capital and SFr8 million in sponsoring pledges.
Both the board and management are confident that the necessary funds will be raised, the statement added.
The idea behind Mystery Park is to present unsolved mysteries of the world in seven theme buildings. These include the enigma surrounding the Egyptian pyramids, the mysterious figures of Nazca in Peru and NASA's quest for extraterrestrial life.
A year after Mystery Park opens, the company hopes to set up a science centre in the middle of the theme park, open to the worlds of science and education.
Development of Mystery Park can be followed at the link below.
swissinfo with agencies