Scores of school pupils who took part in a mass demonstration last month did so during class hours without permission.
Protesters packed out City Square on September 20 as part of a Global Climate Strike.
New figures have revealed 133 of the pupils estimated to have been absent were unauthorised.
As revealed by Wave FM, a total of 877 secondary school pupils were estimated to have been absent because of the strike where political activists and trade unionists took to the streets to protest.
The protest in Dundee was just one of many happening around the country.
Stewart Hunter, convener of children and families services, said: “These figures are out of the ordinary. We would expect the number of unauthorised absences to be significantly lower.
“I am disappointed that so many young people took advantage to try and take a day off. We presumed that they have attended the climate change protest, but the fact it’s unauthorised, we can’t guarantee that.
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“The main disappointment for me with that is I think they have undermined the work of the climate change protesters and, indeed, the young people who had the appropriate permission to take part.
“It’s important that young people are heard and taken seriously, and this is undermined if those who need to hear the message think that young people are just using this cause to take a day off and not taking it seriously. This damages the work that’s being done.”
Mr Hunter added that all schools have a procedure in place for dealing with any unauthorised absences, which involves speaking with parents and potentially taking further action, and this was currently under way.
He said: “With regards to the young people who did participate, I’m really proud that they did take part in the climate change march.
“I think one of the things that we have tried to encourage in our administration in the 10 years that we have been in power in Dundee, is that we want our young people to have a voice, we want them to be engaged and, more importantly, we want them to be heard.
“That’s not just on issues such as climate change but on all issues that affect them, and I think it’s also important we encourage this.
“We want to encourage them to speak out, not just when they agree with us but also when they disagree with us and when they are challenging us.”