SYDNEY -- The Australian federal court has overturned a special law introduced to prevent protesters "annoying" Catholic pilgrims during Pope Benedict XVI's visit to Sydney.

The unusual law, passed by the state parliament of New South Wales State ahead of World Youth Day celebrations and packing a 5,500-dollar (5,335 US) fine, was challenged by activists who claimed it eroded freedom of speech.

As more than 200,000 pilgrims flooded into Sydney for the official start of the Christian celebration, judges Catherine Branson, Robert French and Margaret Stone ruled that a clause relating to annoying and inconveniencing pilgrims went beyond the intention of the state parliament.

The panel ruled that the annoyance clause was invalid because it could not have been the intention of parliament to make such vague and extensive limits to free speech.

"We have interpreted the World Youth Day Act on the presumption that it was not the intention of parliament that regulations would be made under the act preventing or interfering with the exercise of the fundamental freedom of free speech," Justice French said.

"Clause seven is invalid to the extent it seeks to prevent merely annoying conduct."

But the judges dismissed other parts of the challenge mounted by the NoToPope Coalition, ruling that a clause banning the sale of items such as provocative T-shirts did not infringe upon the right to free political communication.