The boost in teacher recruitment sparked by the Covid crisis is expected to be a "short-term gain", the government has admitted.
"Significant gaps" in recruitment in key subjects also remain, despite the "uplift" in trainee teachers, the Department for Education said.
In evidence to the School Teachers' Review Body (STRB), published today, the DfE wrote: "Teaching remains a popular career choice for many. We have recruited nearly a quarter more trainee teachers than last year and have reached a 10-year high of postgraduate applicants.
"While the pandemic and subsequent recession might have boosted recruitment of new trainee teachers, based on the trajectories of previous recessions, we expect this to be a short-term gain. We also continue to see significant gaps remaining in key subjects, despite the uplift in recruitment.
Teacher recruitment: Supply 'remains challenging' in secondary schools
"The supply context remains challenging, particularly in secondary schools, where pupils numbers are projected to grow by 15 per cent between 2018 and 2025."
The admission comes after the government made sweeping cuts to teacher training bursaries for the 2021-22 academic year, sparking a backlash from sector leaders.
James Noble-Rogers, executive director of the Universities' Council for the Education of Teachers (UCET), warned at the time that the effect of the rise in applications could be "short-lived".
"Removing bursaries is a short-term measure that could have long-term implications," he said.
And Emma Hollis, executive director of the National Association of School-Based Teacher Trainers (NASBTT), said: "The immediate increase that we have seen in teacher recruitment does not solve the longer-term recruitment crisis, it only disguises it, and failing to take a long-term view will only store up issues for the future."
The DfE later said that failing to cut teacher training bursaries for the next academic year would have been indefensible, given the rise in applications sparked by the Covid crisis.
Speaking at the UCET annual conference, a senior DfE official said the "radically reduced" bursaries package for 2021-22 was justified by a "surge" in interest in teaching and "a very challenging time...economically for the country".
Research conducted last year found that the Covid-19 recession had reignited interest in the teacher training sector – with a 35 per cent year-on-year increase in applications between March and August.
The overall number of postgraduate teacher training applicants up to mid-August 2020 was 16 per cent higher than at the same point in 2019, and 14 per cent higher than the 2017-19 average, according to a report by the National Foundation For Educational Research.