Teaching staff at Cambridge University are to hold protests during open days this week to alert parents and prospective students to the problem of insecure employment at the institution.

Two-thirds of Cambridge teaching staff are paid by the hour and three-quarters do not have a contract, according to the University and College Union (UCU). Protesters say the precarious nature of their work is impacting on mental health and some are struggling to pay their bills.

On Thursday, protesters will stage a bike parade around the university, with banners, flags and music, and hand out leaflets highlighting “exploitation” of teachers, as well as a 19.7% gender pay gap at Cambridge. The sector average is 15.1% average.

“We haven’t taken the decision to protest at the open days lightly,” said the Cambridge UCU representative, Jenny Marchant. “But the university needs to understand that a true world-class institution respects its staff.

“Cambridge prides itself on its unique model of teaching based on one-to-one or small-group supervisions and the way this model has been developed has led to the exploitation of staff.

“We have staff that are suffering from extreme levels of financial and personal hardship. Some don’t have enough money to pay for food or rent, while others are seeking to leave the sector because they can’t make ends meet.”

One academic paid hourly to teach at Cambridge said: “There is no job security because there are no contracts and the pay, once the preparation time is factored in, often equates to less than the minimum wage.

“There is also not enough work to make up a full-time job. This, when one considers living costs in Cambridge, means that it is almost impossible to subsist without either a second income or a private income.

“I came to Cambridge as an undergraduate from a non-selective state school. At the time, I thought that I was being aspirational; I now realise that I would have been better off stacking shelves in my local supermarket.”

Staff at Cambridge are not alone. Casualisation has transformed employment in the higher education sector in recent years. A new UCU report based on a survey of almost 4,000 casualised staff found that many are being forced to do multiple jobs just to survive.

Some have put off long-term plans such as starting a family or buying a house because of the lack of job security. More than two-thirds of respondents (71%) said their mental health has been damaged by insecure employment. More than two-fifths (43%) said it had affected their physical health.

The report warns casual contracts are also having a detrimental impact on research and the education students receive. One respondent told the UCU they do three jobs at any one time and never know when they will be paid. Others said that because they are not entitled to sick pay, they cannot afford to take time off when they are unwell.

UCU’s acting general secretary, Paul Cottrell, said: “Students would be shocked to learn that many of their lecturers are forced to take on multiple jobs and are struggling to pay the bills. Universities need to understand this is a real problem that must be dealt with, not excused or underplayed.”

Commenting on the open day protests, Cambridge University said there were ongoing discussions with the unions to address concerns about the use of fixed-term and casual contracts. It added: “A working group, which includes union representatives, has met on an almost monthly basis and we believe that we are continuing to make progress. We remain committed to working with the unions to try to resolve these issues.”