Some Otago University students say they intend to turn a parliamentary bill aimed at making student union membership voluntary into an election issue.
About 150 students protested on Friday at the opening of the redeveloped university library by Prime Minister John Key.
By filibustering in Parliament the Labour Party has been holding up debate on the controversial Education Freedom of Association Amendment Bill for several months.
The private member's bill is sponsored by ACT member Heather Roy and supported by the National Party.
The president of the Otago University Students' Association, Logan Edgar, says the protest shows a wide range of students are united against the idea.
Mr Edgar says students have been too quiet in their opposition to voluntary student unionism, and will take the fight to the Government if they have to.