A US professor who showed how users could successfully manage common property became the first woman to win the Nobel prize for economics on Monday, sharing it with an American expert on conflict resolution.

Elinor Ostrom defied conventional wisdom with studies that showed that user-managed property -- such as fish stocks or woodland areas -- more often than not was better run than standard theories predicted.

The previously accepted view was that common property was poorly managed and should be either regulated centrally or privatised.

The Royal Swedish Academy of Sciences awarded her half the 10 million Swedish crown ($1.4 million) prize, with the other half going to Oliver Williamson, who was recognised for his analysis of conflict resolution by firms and markets.

"Over the last three decades, these seminal contributions have advanced economic governance research from the fringe to the forefront of scientific attention," the committee said in its statement.

Indiana University Professor Ostrom, reached by telephone for a news conference, said her first reaction was "great surprise and appreciation".

"There are many, many people who have struggled mightily and to be chosen for this prize is a great honour and I'm still a little bit in shock," she said.

The academy said Ostrom and Williamson, of University of California, Berkeley, helped explain that economic analysis can shed light on most forms of social organisation.

"Economic transactions take place not only in markets, but also within firms, associations, households, and agencies. Whereas economic theory has comprehensively illuminated the virtues and limitations of markets, it has traditionally paid less attention to other institutional arrangements," it said.

The economics prize, officially called the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel, was established in 1968. It is not part of the original group of awards set out in dynamite tycoon Nobel's 1895 will. - Reuters