Teachers at Menzieshill High are demanding assurances over their jobs, amid concerns about the school’s future.
Educational Institute for Scotland representative David Baxter said teaching staff are being kept in the dark about where they would end up if city councillors agree to close the school.
A vote will be held on June 22 to decide the fate of the school, which has been backed for closure by Education Scotland.
Mr Baxter said: “Principal teachers in particular are worried for their positions, as there are obviously fewer of these posts in the city and there are already teachers in promoted posts at schools throughout Dundee.
“What is also worrying is that, as far as the council is concerned, it is still business as usual ahead of the vote, which means teaching posts and promoted posts are still being advertised.”
A Dundee City Council spokesman said: “Full reports on the school estate review consultation will be considered by the education committee on Monday June 22.
“A decision will be made then by the education committee. Trade unions have been fully briefed in relation to the consultation process.
“The head of secondary education has also met with all staff twice at Menzieshill High to discuss the situation and will talk to them again once the education committee has reached a decision.”