TUV leader Jim Allister has expressed concern over the election of the new president of the Students' Union at Queen's University Belfast.
It comes after social media posts by Grian Ni Dhaimhin, in which she appeared to signal her sympathy for militant republicanism.
Among them was an image of a poster for a commemoration event for three IRA members shot dead by the SAS at a Strabane arms dump in 1985.
The Strabane history and social anthropology student (23) also 'liked' various posts, including one showing a masked woman with an assault rifle alongside a republican slogan.
Her election campaign had included achieving a carbon neutral university and opposing slum landlords.
Ms Dhaimhin has since deleted her Twitter account.
In January Mr Allister met the university's Vice-Chancellor Professor Ian Greer to express concerns about Queen's being "a cold house for the unionist community" and how it can be addressed.
The North Antrim MLA said yesterday: "There was great reluctance to accept that there was a pro-nationalist bias within Queen's but the events of recent days form part of a concerning pattern both within the union and within the university itself.
"In May the University College Union (UCU) criticised me for daring to question the right of a former member of staff at Queen's, Professor Brian Walker, to call for me to be banned from the airwaves.
"Bizarrely the UCU claimed that questioning the right of an academic to call for the gagging of politicians amounted to an 'outrageous attack on democracy and the values of free speech that our society holds dear'."
Mr Allister added: "Add to that the fact that a 'Brits out' poster was displayed at the Freshers' fair last September and the latest revelations about SU president elect, I believe any reasonable observer will agree that it is time for Queen's to get its head out of the sand in relation to its relationship with the unionist community."
Sarah Foster, daughter of First Minister and DUP leader Arlene Foster, is among 1,500 people who have signed a change.org petition, entitled 'End the Sectarianism towards Protestants and Unionist Students at QUB', which was set up after unionists reacted with alarm to the election of Ms Ni Dhaimhin.
Members of the QUB Democratic Unionist Association have called on Ms Ni Dhaimhin to apologise for her comments, which they say "have caused a great deal of hurt".
A spokesperson for the group said last night: "There should be no place for the glorification of terrorism within Queen's University, and the new president should recognise the hurt her posts have caused and apologise.
"Our members have signed the petition in relation to this issue and we plan to meet with university representatives to highlight the need for an apology from the new SU president. Our association has met with the public engagements team on a number of occasions to address issues impacting upon students from a pro-Union background.
"Unfortunately, the election of the new president will reinforce the image of Queen's amongst many as a 'cold house for unionists'.
"We look now to the Students' Union to demonstrate what action they intend to take to demonstrate that Queen's University Students' Union is welcoming and representative of all students."
On Facebook the QUB Conservative and Unionist Society also called on Ms Ni Dhaimhin to apologise.
A QUB spokeswoman said Ms Dhaimhin will take up her position on July 1 and that once in post, "the SU President, as with all Student Officers, is required to adhere to a Student Officer Protocol, detailed in the Constitution of the SU, which details responsibilities and conduct relating to their role".
QUBSU did not reply to a request for comment when contacted yesterday.