BOSTON (AP) – Massachusetts Turnpike Authority Chairman Matt Amorello, who oversees the beleaguered Big Dig highway project, filed a lawsuit Monday seeking to prevent the governor from ousting from his $223,000-a-year post.

In the lawsuit, Amorello asks a single justice of the Supreme Judicial Court to block Gov. Mitt Romney from demoting him and to prevent a hearing from taking place where the governor is supposed to act as judge and jury in seeking his ouster.

Amorello has been under fire over the past several years as Romney has criticized his management of the Big Dig. In the two weeks since 12 tons of ceiling panels from a Big Dig tunnel collapsed, killing a 39-year-old Boston woman, Romney has renewed his calls for Amorello’s ouster – and said the accident shows that he’s incapable of overseeing the $14.6 billion highway project.

Amorello’s lawyers contend that the governor does not have the authority to demote him.

The governor’s move would strictly strip Amorello of his position as chairman and CEO, but he could remain on the five-member board, a position that pays about $25,000 a year.

“The governor has invented a power he does not have,” according to the 12-page lawsuit.