AUSTRALIAN schoolchildren's results in maths and science have flat-lined over two decades, while their reading ability is lagging many developed nations, including the United States, England and Canada, new reports show.

The federal School Education Minister, Peter Garrett, said the release of two international studies of reading ability and maths and science proficiency was a ''wake-up call'' that showed ''performance problems in every state, in every school sector''.

Australia ranked 27th out of 45 countries for reading, with 21 of those countries performing significantly better. Hong Kong topped the rankings, with Finland, Russia, the US and England outranking Australia.

Australia's mean score for reading was similar to that of Poland, Lithuania and New Zealand.