The Polish president, Aleksander Kwasnieski, has vetoed a law that would allow victims of Communist era oppression to see their secret police files.

The president's opponents, who hold a majority in parliament, say he is defending his former Communist colleagues.

Mr Kwasnieski says the files should be open to all Poles, not just victims of the past regime.

The bill now returns to parliament, which has the authority to overturn the president's veto.

The government parties are more than twenty votes short of the sixty percent margin required to overturn the veto.

A BBC correspondent in Warsaw says the issue is a highly sensitive one in Poland.

Last week a new law came into effect requiring all senior state officials to disclose past collaboration with the Communist regime or be banned from office for ten years