They had wanted to deliver a personal message to prime minister Najib Abdul Razak tonight but a group of student activists were left holding up their protest placards at his official entourage as the fleet of cars left the Universiti Malaya campus.

Kesatuan Mahasiswa Malaysia chairperson Anis Syafiqah Md Yusof said it was "strange" for Najib's official car and entourage to have exited through the main gate facing Kerinchi but entered through another gate nearer to Petaling Jaya.

"Maybe they knew that we would be here. But we hope that no matter what, Najib will see our message," said Anis Syafiqah.

Among others, their placards bore the message "Tangkap MO1" - "MO1" being the the code name mentioned in the United States Department of Justice’s civil suit to recover nearly US$1 billion in 1MDB-linked assets.

Critics have maintained that "MO1" could only be referring to Najib. Attorney-general Mohamed Apandi Ali, however, had since last January cleared Najib of all wrongdoings.

Najib had earlier held a special dialogue session on his 30-year national transformation plan, or TN50, at UM's Chancellor Hall.

Earlier, Anis Syafiqah and a group of some 15 student activists had called on Najib to reform the administration of public universities as part of the TN50 plan.

"We have heard the prime minister said he would listen to the voices of all the rakyat. He wanted to adopt a bottoms-up principle.

"So, if that is really true, then why are not all students invited for the function tonight?," Anis Syafiqah told reporters outside the main gate of Universiti Malaya.

Najib's official car was earlier expected to pass through the gate to enter the university's compound. 

She further questioned whether Najib and the government were only interested in listening to voices supportive of their views while silencing the critics, including by taking disciplinary actions against 13 university students since late last year.

"Why was the event held behind closed doors and the attendance by exclusive invitation only?

"Is this the (only) voice that the government wishes to listen to?," asked Anis Syafiqah who had been suspended for one semester by UM over participation in the "Tangkap MO1" rally last August.

Student activist Ashraff Nazrin Nor Azman claimed that Malaysia and Thailand were the only two countries in the region which had taken actions to silence students.

"The main thrust of TN50, for us, should be a reform of institutions of higher education.

"This is crucial so that students in public universities can be free to speak up and voice their views," he said.

Student Unity Front president Asheeq Ali Sethi Alivi, meanwhile, pointed how former US president Barack Obama himself had supported the students' show of protest against the Trans-Pacific Partnership Agreement (TPPA), during his townhall session at UM in 2014.

"There were students who had raised anti-TPPA placards during the townhall (with Obama) but the US government later sent a letter of support (on the students' right to protest).

"So we hope that now Najib will do the same thing as Obama had done," said the UKM law student, who had also been served with a one-semester suspension order.

The students earlier lit candles for a vigil held in solidarity with their friends who had faced or were facing disciplinary actions.