Lecturers from Oxford University and Oxford Brookes University are among those taking part in a 48-hour strike this morning in a dispute over pay.
Members of the University and College Union (UCU) will also refuse to work overtime, set additional work, or undertake any voluntary duties like covering timetabled classes for absent colleagues.
From 8am to 10am staff picketed at the Old Road Campus Research Building in Headington and at the entrance to the University Science Area opposite Keble College.
The union has rejected a 1.1% pay offer from employers, arguing that universities could afford to pay more after the pay and benefits of university leaders went up by 5.1% last year.
Married father-of-two Garrick Taylor, 35, vice president of the UCU Oxford branch, joined about 30 staff at Old Road.
He said: "I have been at Oxford University for the past four years and we keep getting these below-inflation pay rises, which is eroding our pay.
"I live in Winchester and I have taken a part-time job as a firefighter to boost my income - I know a lot of people who have taken second jobs."
Terry Hoad, president of the UCU Oxford branch, added: "We obviously can't picket every university site because there are too many of them.
"Our members are strongly behind the claim that the union has made nationally.
"The issue of insecure contracts is a big issue in Oxford - a lot of people are employed on fixed-term contracts, particularly in science departments.
"It's a precarious position for people to be in, not knowing if they are going to have a job in a couple of years' time."
If the dispute is not resolved in the coming weeks, members have agreed to further strike action which could affect open days, graduation ceremonies and the clearing process.
The union is also beginning preparations for a boycott of the setting and marking of students' work to begin in the autumn.
UCU general secretary Sally Hunt said: "A 1.1% pay offer is an insult to hardworking staff, especially in light of the 5% pay rise vice-chancellors have enjoyed while holding down staff pay. Members have made it clear that they won't tolerate a continued squeeze on their income, pay inequality and the increasing job insecurity blighting the sector.
"It's time to invest properly in the teachers, researchers and administrators who are the backbone of our universities. Industrial action which impacts on students is never taken lightly, but members feel that they have been left with no alternative. If the employers wish to see a swift end to this dispute, and avoid further disruption, they need to come back to the table with a much-improved offer."
Protests are planned around the UK and Unite, which has around 12,000 members in the higher education sector, said it was consulting on the possibility of joining the action. A ballot closes on June 6.
National officer Mike McCartney said: "We are calling on Unite members to reject the offer on the table.
"They have seen their pay slashed over recent years, while many university bosses are raking in more than the Prime Minister.
"Clearly there is unfairness in the pay system and that hurts our members who are mainly technicians, porters and cleaning staff without whom universities would not function. These are the workers who are the key to providing a good student experience."
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