Casual staff at the University of Queensland have lost 17 weeks of work while students stranded in China have received letters warning them they will fail if they don’t pay semester fees on time, a teacher at the university has said.

Approximately 40 casual teaching staff at the University Of Queensland’s Institute of Continuing and TESOL Education (ICTE) have been affected as the Australian government’s ban on travellers from mainland China causes an unprecedented drop in student numbers.

The coronavirus-driven travel ban, which is about to enter its fourth week, has affected some 6,300 students at the University of Queensland. The ICTE provides English language training, including bridging programs for international students who wish to go on to study at the university.

Francine Chidgey, a casual teacher at ICTE, told Guardian Australia that she and other members of staff had had their shifts cut without warning since the travel ban was instituted.

“About half our students are from China, mostly in bridging English,” said Chidgey.

“I’ve been told that I won’t have teaching shifts for 17 weeks. About 40 of my colleagues are in the same position, with others receiving only one or two days’ work per week, and occasional relief work.”

The travel restrictions have hit the higher education sector particularly hard, with universities reportedly projecting $1.2bn in lost fees from an estimated 65,800 international students at risk of cancelling their enrolment due to being stranded outside Australia. The government has said it will consider relaxing the ban at the end of the month.

Chidgey said that in previous years staff at ICTE could expect at least a few shifts per week at this time of year.

Her comments echoed those made by a lecturer at the University of Sydney on Wednesday, who said casual staff there were “panicking” at the prospect of lost shifts, and that many who were still working were resorting to “unsustainable” methods of communicating with students who were stuck overseas.

“In other departments, colleagues have told me they’re snowed under trying to adapt materials for lectures and tutorials to be offered online. They haven’t been paid overtime for this demanding work,” Chidgey said.

Stranded students were also concerned that they couldn’t access the websites they needed from China except through VPN, and that sites themselves, such as Blackboard – a common online educational tool used by universities – are confusing and frustrating, she said.

“No clear instructions have been emailed to them. As a teacher I agree the websites are not set out intuitively and are frustrating to navigate,” Chidgey said.

She said students who have been stuck in China due to the coronavirus travel ban have also received emails warning that they would fail the semester if they did not pay their fees on time.

Chidgey said the tone of the emails was “completely insensitive”.

“My students told me they’re disappointed by the university’s response, and that the academic and financial stress was exacerbating their stress over the health crisis itself.

“This has been done to safeguard the university’s profits. It certainly hasn’t been done to deliver a quality online educational experience to Chinese students affected by the travel ban, or to pay overtime to other staff struggling to provide supplementary online materials themselves without proper resourcing or support.”

Chidgey said she understood the university was worried about the impact the travel bans were having on staff. “They want to reassure us that we feel valued. But how can we feel valued when we don’t have work that we’re relying on?”

A spokesperson from the university said its provost had met with the National Tertiary Education Union (NTEU) earlier this week and that it was a positive meeting.

“This is an unprecedented situation, and still evolving,” said the spokesperson.

“We have been providing regular updates directly to affected students via email and through our FAQ pages. This includes information about their options to start studying with us remotely for weeks one to four as an interim measure, and how they can defer if that is the best choice for them.”

The university also said it had been “transparent with our staff about the possible flow-on impacts for the university” from the crisis.

“Staff have been asked to take a prudent approach to expenditure, and it is acknowledged widely that we will all need to ‘chip-in’ and do things differently. We truly value the work being done, and we will recognise staff for the additional work required.

“We are looking at a range of options that include redeployment of resources to support students continuing their learning remotely and absorbing as much of the cost as possible into non-staff areas. Also, depending on when students arrive, we foresee a need for additional learning support for these students.”

The University of Queensland was one of the first three institutions globally tasked by the Coalition for Epidemic Preparedness Innovations to develop a vaccine for Covid-19.

The NTEU has called for universities to ensure casual staff who would normally expect to return to work at the beginning of semester are not deprived of income or hours of paid work due to the travel ban.

“Many of our casual members have not had paid work for months over the Christmas period and the prospect of losing hours as a result of the coronavirus is a material and pressing concern for them,” NTEU president Alison Barnes told Guardian Australia on Thursday.

The union has also written to the minister for education, Dan Tehan, to request a support package for the sector.