Teachers claim there is now such a shortfall, after staff rushed to sign up for the offer before the December 1 deadline, that pupils risk missing out on studies and may suffer psychological damage.
More than 3,000 primary and high school teachers have left their posts to take advantage of a last-chance offer to retire early at 50 with a pension set at up to 80 per cent of their final salary.
As of January 2004, the minimum age of retirement will be raised to 65 for men and women - from 60 and 55 respectively now - and those who opt for it will only receive up to 50 per cent of final pay.
In Vienna, at least 700 teachers took early retirement, with schools losing up to six teachers in one go. Classes have had to be amalgamated and teachers have had to transfer schools to help fill the gaps. Most extra-curricular activities have fallen by the wayside.
Teachers and trade unions took to the streets when the government announced it would not be providing replacements. It said regional governments would have to fund replacements.
Government child psychologist Harald Aigner said the sudden departures mid-year would have a negative effect on pupils' psychological well-being.