Heavy rain washed out day two of the five-million-dollar HSBC Champions here on Friday, forcing organisers to consider the possibility of extending the tournament into a fifth day.

Sweden's Henrik Stenson is the leader after the first round on seven under, one stroke ahead of an elite four-man pack of American duo Phil Mickelson and Anthony Kim, Spain's Sergio Garcia and Australian Adam Scott.

Round two was due to tee off on Friday morning at the Sheshan International Golf Course but overnight rain persisted throughout the day, forcing organizers to declare a complete washout.

Officials said they still hoped all 72 holes of the tournament would be played, and scheduled the start of round two to begin early on Saturday.If the weather is clear, players would fit in at least 27 holes on Saturday and play the end of their third round on Sunday, then immediately start their final round.

But organizers left open the possibility of players having to complete the tournament on Monday, meaning a host of the world's top golfers from Europe and the United States would have to stay an extra day in Shanghai.

"Our prime objective and our current intention is to complete 72 holes in the HSBC Champions," European Tour tournament director David Probyn said in a statement.

"Clearly, if we have any further delays... there is a strong possibility that play in the fourth round may need to be completed on Monday morning and this has been provisionally agreed with all parties in the tournament." Clearer weather is forecast for Saturday and Sunday, although there is still the possibility of more rain.

The HSBC Champions has attracted one of the best fields ever for an Asian tournament, with 11 of the world's top 20 ranked players in Shanghai.

A duel between Mickelson and Garcia for the world's number two ranking has added spice to the event, co-sanctioned by the European and Asian tours. Prayad Marksaeng, Thailand, is the best of the Asian Tour's contingent, sitting in a pack of six players on four under.