Aussie rowers wait on Oly medal hunt

The Australian men's quad scull must wait another 24 hours to push for an Olympic gold medal with racing cancelled for the day as rain and gusty winds lashed the Lagoa Stadium course.

The crew, who are hot favourites, were due to race for a medal mid-morning but the decider has been rescheduled for 10:12am on Thursday (2312 AEST Thursday).

It's the second day rowing has been cancelled and organisers have been forced to shuffle races.

They still have the option of extending the program to Sunday should the poor conditions continue.

The Australian men's four were due to contest their semi-final on Wednesday, while the women's eight were set to line up in the repechage but they too will now row on Thursday.

The four are now up at 9:30am (2230 AEST Thursday) with the top three boats advancing to Friday's final.

The eight row at 9:50am (2250 AEST Thursday), with the top four going through to Saturday's medal race.

World champion Kim Brennan, who is favourite for gold in the women's singles scull, was due to race in the semi-final on Thursday but it has been put back to Friday as has the men's event, with Australian Rhys Grant in action.

The single scull medal races are on Saturday.