One man was killed and several buildings torched in violence at a university in Papua New Guinea, its vice-chancellor said Sunday, some two weeks after police opened fire on students in the capital.

Students have been protesting against Prime Minister Peter O'Neill, who is being investigated for corruption.

The undergraduate killed at the campus in Lae, the country's second-largest city, was reportedly targeted amid clashes over class boycotts called as part of the protests.

"We believe it is the same group (that killed the student and burnt the buildings)," said Albert Schram, vice-chancellor of Papua New Guinea University of Technology.

He said several dozen men carrying stones, sticks and bush knives mounted the attack on Saturday night, "and they moved about very fast, so it was very difficult for our security forces to follow them or arrest them".

Schram said the student, believed to be in his early 20s, was at a dormitory on campus when he was hurt in the "apparent targeted attack" and died several hours later.

Schram told AFP the attack may have been revenge for a brawl about two weeks ago between students who supported prolonging the boycott and others who wanted to call it off.

"In that brawl, there was one student that was wounded, and possibly this is a revenge attack for that victim."

Schram said the group then set fire to several academic buildings, which suffered significant damage.

They outnumbered police and campus security officers "for some time" but were finally dispersed with tear gas early Sunday, he said. Police could not immediately be reached for comment.

Separate clashes between security guards and students broke out at the University of Papua New Guinea in Port Moresby on Thursday, PNG's Post-Courier reported.

Students have been locked in a standoff for more than a month with authorities in the impoverished Pacific nation north of Australia, as they demand O'Neill step aside over corruption allegations which he denies.

Some 23 people were hurt including five critically when police opened fire on June 8 on students.