"AUTSA absolutely supports and respects the right to protest, but it has to be ethical and moral. By withholding students' grades it is putting them under even more stress and pressure when they are in the middle of exams.
"I have been hearing students wondering about their marks over the past few weeks and what the next few months will look like for them.
"The uncertainty around how they have gone in their final assignments is causing undue stress and anxiety, and is having an impact on their mental health and wellbeing."
It was also creating a risk that some might not be able to graduate during the December ceremonies.
"If students want to appeal their grades, there may not be enough time to resubmit and have them marked before graduation. Also for international students, who have their accommodation and visas to worry about, it is adding even more stress."
TEU national industrial officer Irena Brorens said their members had "overwhelmingly" rejected AUT's latest offer.
Three years was too long for their lowest-paid members, some of whom were on $17.50 an hour, to wait for the living wage, she said.
"You can't live in Auckland on a wage like that, and the majority of our members feel very strongly about this.
"Many employers, including Auckland Council and government sectors, are paying the living wage, so why shouldn't AUT?"
Brorens said they acknowledged AUT had responded to their strike with an improved offer, but it did not go far enough.
They also acknowledged the impact on students, she said.
"We are aware it could have an impact on students, but they can always go to their lecturer if they are concerned about how they are going, or about the exam process."
Recently more than 1000 staff and students signed a petition calling on
the vice chancellor to pay staff the living wage.
AUT people and culture group director Beth Bundy said the university had presented TEU and the Tertiary Institutes Allied Staff Association (TIASA) with a "revised improved offer" on Monday.
"AUT considers this a good offer which is at the top end of current offers in the sector.
"The offer will also achieve the removal of rates under $20.55 for all employees.
"Unlike some other sectors, the university sector has not received additional government funding for salaries."
AUT was seeking a future date to continue negotiations, Bundy said.
AUT vice-chancellor Derek McCormack said the timing of the strike action was concerning.
"We are concerned that one union, the TEU, is conducting strike action designed to affect students at a time when they should be able to fully focus on their final exams and assessments.
"We are taking all practical steps to minimise the impact on our students including providing marks to students verbally on request.
"At this stage the strike action will not affect the ability for students to graduate in December."