International schools in China fear that they are "running out of time" to run a normal summer exams season due to the impact of coronavirus.
Their warning came as major international exam boards extended the deadlines for pupil entry because of schools closing due to the outbreak.
Cambridge International, an exam board that administers IGCSE and international A-level qualifications, has said it is "constantly reviewing" the situation and will be checking Chinese government guidance to monitor arrangements for the summer exam series.
However, it said it expects the summer exams to go ahead as normal.
But Olly Wells, the principal of Rong Qiao Sedbergh School in Fuzhou, China, said: "We are running out of time really. It’s not certain what the impact will be – the longer this goes on, the more chance there will be a negative impact.
"If this goes on for longer, children won’t have time to prepare, and an entire year can’t retake their exams, although I do think schools will reopen soon.”
He warned that the outbreak could also have practical impacts such as whether it would be possible to transport exam papers to China.
"Some [exam boards] have delayed their entry deadlines for A levels and IGCSEs, and once we’re all reopened we’ll decide whether we can go through the exams as normal or whether there will be contingency plans," he told Tes.
“It’s not very clear at the moment. For example, can the boards successfully ship the papers over here when the virus is dying down?
A spokesperson for Cambridge International said: “We are working closely with Cambridge schools affected by school closures and other local restrictions as a result of COVID-19 (the coronavirus) and are giving them as much support as we can at this challenging time.
“We are constantly reviewing the situation, and we expect to run the June 2020 exam series in China, but will monitor government guidance about school open dates.
"We have extended the deadline for making June 2020 exam entries for affected schools in China and most schools have submitted their entries.
“We are looking at other ways in which we can provide more support to Cambridge schools in China, including providing access to extra online teaching and learning resources and online teacher training courses."
Mr Wells fears there will still be difficulties for schools. “The exam boards have their own contingencies, but the inconvenience is over things like practical exams, for example, music and art," he said.
Some international schools in mainland China have been closed since the start of the month because of the outbreak.
A spokesperson for Pearson, which also administers IGCSEs, said the May and June 2020 exam series was scheduled to go ahead as planned, but that the board had extended the entry deadline in greater China while schools remain closed.
The spokesperson said: “We are committed to supporting our customers and ensuring that learning can continue during this period of uncertainty.
"We have a number of arrangements in place for our customers and students in Greater China (mainland China, Hong Kong, Macao, Taiwan).
“We have made digital editions of all International GCSE and International A-level student textbooks available free of charge to all of our centres in Greater China.
“Our priority is to protect the health of students, parents and schools, and safeguard against the spread of the virus. We are monitoring the situation closely as it continues to evolve.”