The teachers union and state officials argued Tuesday that a lawsuit challenging New York’s tenure policy should be tossed because Gov. Cuomo and the Legislature approved a new law tightening teacher accountability.

The changes make the tenure suit moot, lawyers defending the state claimed during oral arguments in Staten Island Supreme Court.

“We live in a different world ­today than when this action was filed,” said Assistant State Attorney General Steven Banks.

Cuomo and lawmakers approved in April a tougher tenure law that more closely links teacher job ratings to the test scores of their students. The new law also awards tenure after four years instead of three.

But a lawyer for education activists insisted the revisions were mere window dressing and said the law still protects bad teachers.

“The changes [in tenure rules] are almost nonexistent to the core allegations [of the lawsuit],” said Jay Lefkowitz, representing plaintiffs affiliated with activist Campbell Brown’s (left) Partnership for Educational Justice and the NYC Parents Union.