“We don’t actually need such an act to control the students,” said Adam Ali, a student activist and member of Progressive Students Legacy, a student organization at Sultan Idris Education University. “Why must we control the students? They know their rights — they can practice their rights. With the current amendment of the U.U.C.A., what happens now is that they are again controlling the students.”

Under the amendment, students who hold any political post will be prohibited from conducting political party activities on campus. Students could also be prevented from joining any organization that the university’s board deemed “unsuitable to the interests and well-being of the students or the university.”

Mr. Haziq said he was concerned that universities could make arbitrary decisions about which organizations students could join.

The original amendment included a clause that would have banned students who held political posts from being elected to positions in student organizations, but lawmakers voted unanimously to remove this clause before the bill was passed. The clause had been widely criticized, including by members of the prime minister’s own party.

Parliament rejected the opposition’s attempts to remove several other clauses, including the provision that prevents students from “expressing support or sympathy” to an unlawful society or organization the university deems unsuitable. Tian Chua, vice president of the opposition People’s Justice Party, described the reforms as “half-hearted” in a Twitter post: “Where is the promised freedom for the young people?”

Mr. Najib’s pledge that students would be permitted to participate in politics came after a court ruled last October that the National University of Malaysia had breached the Constitution by taking disciplinary action against four students who took part in political campaigning during a by-election in 2010.

Before the enactment of the act, Malaysian campuses used to be home to vibrant student activism, with many of today’s leaders, including opposition leader Anwar Ibrahim, cutting their political teeth on campus. Mr. Haziq said that since the law was introduced, the student movement had lost its momentum, with most students now afraid to take part in politics because they were worried that they could be expelled.