Staff at Queen's University Belfast and Ulster University are taking part in a UK-wide three-day strike action over pay and conditions.
Workers at 58 universities are taking part in the action following a breakdown in negotiations with employers over pension cuts, pay and what the University and College Union (UCU) has termed worsening working conditions.
The UCU says staff pay has fallen by 20% after 12 years of below-inflation offers, while almost 90,000 academic and academic-related staff are employed on insecure contracts.
The union is demanding employers revoke pensions cuts, award a £2,500 (€2,939) pay increase for all staff, and take action to tackle unmanageable workloads, pay inequality and insecure contracts that blight the sector.
Professor Dominic Bryan is among staff taking part in the action at Queen's.
He told BBC Radio Ulster's Stephen Nolan Show that, while he feels he is paid enough, there are "lots of low-paid people at Queen's".
UCU general secretary Jo Grady said staff are asking for the "bare minimum in a sector awash with money".
"But, sadly, the only time vice chancellors seem to listen is when staff take action, and those leading our universities should not under-estimate their determination to change this sector for the better," she said.
"We are grateful to all the students who are supporting staff taking industrial action because they understand that staff working conditions are student learning conditions.
"Vice chancellors now need to concentrate on asking themselves why strikes have become an annual occurrence and seek to resolve this dispute in order to avoid more needless disruption to learning.
"If they continue to ignore the modest demands of staff then we will be forced to take further industrial action in the new year, which even more branches will join."