Warsaw  - Millions of Polish schoolchildren had a day off school Tuesday as teachers throughout the country went on strike.

Half of all schools had no classes, a spokesman from the Ministry for National Education said in Warsaw.

According to the teachers' union, ZNP, at least two thirds of the 30,000 schools and kindergartens were closed.

In the province of Swietokrzyskie, central Poland, 84 per cent of schools were on strike while in the southern city of Opole and in West Pomerania, north-west Poland, only
17 per cent were on strike.

The unions had appealed to parents not to send their children to school Tuesday.

Teachers are demanding a doubling of their salaries up to 2010. Newly-qualified teachers receive a starting salary of 1,218 zloty (551 dollars) Experienced teachers receive 2,200 zloty, less than the average wage of 3,000 zloty. The government's offer of a pay increase of 12 per cent this year is not considered sufficient by the ZNP.

Unions are also opposed to the planned abolition of special regulations for teachers including the right to retire after 30 years of service, regardless of age.

If the government does not meet their demands, teachers plan to take more long-term strike action from the beginning of the new school year in September. (dpa)