The Wildcats have been mired in financial strife for the last month and new chairman Michael Carter last week warned the club had a shortfall of around £400,000, with prop Amor the latest to depart the Rapid Solicitors' Stadium to raise funds.
Half-backs Kyle Wood and Tim Smith have signed for Huddersfield and Salford respectively and while winger Ben Cockayne is expected to join Hull KR soon, Wakefield are desperate to hang on to star man and captain Danny Kirmond, who was named in the Super League Dream Team on Monday.
Amor becomes Saints' fourth signing for next season, after Penrith Panthers duo Luke Walsh and Mose Masoe and Richard Beaumont from Hull KR.
Saints head coach Nathan Brown said: "Kyle is a young British prop forward who is already one of the best front-rowers in Super League. He will add strength, size and dynamism to our pack and is a great long-term recruit for the club."
The 26-year-old has made 76 Super League appearances in his career and this season has made close to 3,000 metres for Wakefield.
Chairman Eamonn McManus added: "There was understandably a lot of competitive interest in Kyle and we are delighted to have secured him on a long-term deal.
"He is another key addition to the squad which we are putting together for next season and beyond.
"There are many reasons to be excited and confident about the future."
- Sports & Recreation
- Kyle Wood
- Super League Dream Team
- Super League
- Danny Kirmond