Howe currently works for architectural firm Grimshaw but is leaving to set up his own company, which is to be called The Ministry of Architecture.
As the island is within international waters, being six miles off the coast of Felixstowe, any casino built on it would be exempt from UK gambling laws.
Howe would not reveal details of the scheme, but said he has been working on designs over the past year.
There have been proposals for the site before, but these plans are different
Dominic Howe, architect
He said: "There have been proposals for the site before but these plans are different. I've studied the original plans from the 1930s and drawn up ideas for an ecologically sustainable project."
The site consists of two hollow concrete cylinders that rise 60 m out of the sea to support a 6000 ft2 deck with a low-rise building and a helipad. It is owned by 78-year-old millionaire businessman and former pirate radio DJ Prince Roy Bates, and is currently rented to an IT firm called HavenCo.
The former anti-aircraft platform was built by the government in 1939 to deter German bombers. In 1967, Roy Bates bought the site, declared it his own country and proclaimed himself Prince Roy of Sealand.
The island has its own stamps, coat of arms and even its own passport. Members of the Bates family claim to have defended their territory with guns against "armed attackers" more than once in the past.