Roy Burke said the expiry of an agreement with Dutch company Verweij and Partners meant no-one now had exclusive rights to work on the site.
The company had originally pledged to start redeveloping Fort Tourgis by the end of 2012.
Plans for the Victorian fortification include a hotel and conference centre.
Mr Burke said: "Verweij and Partners no longer have exclusivity on Fort Tourgis... nobody has the right to build or develop Fort Tourgis."
He added: "If they come along with plans tomorrow, the States of Alderney would have to relook at those plans and decide whether or not they want to proceed with that development."
Verweij and Partners entered into negotiations with the States of Alderney in 2007.
The company submitted plans for a resort, which would include spa facilities and 50-70 bedrooms.
Mr Burke said any development would need to involve much work to the inside of the fort, due to the fact that many of the floors have rotted and collapsed.
He said: "Virtually all the original features will have to stay.
"From an economic perspective there's no doubt it will be a great boon for Alderney."
Mr Burke said he would be meeting a representative of Verweij and Partners in a few weeks, and was expecting an update on the development.
He said following an announcement earlier in the year that part of the company had been declared bankrupt, he was examining its finances.
Attempts to contact Verweij and Partners were unsuccessful, with the company's phone lines in the Netherlands appearing to have been disconnected.
An agreement on the redevelopment of Alderney's derelict Fort Tourgis has lapsed, according to the chief executive of the island's States.