20 July 2012 Last updated at 15:24 ET

London 2012: Rowing park and ride tickets still unsold

Organisers expect 25,000 people to visit Eton Dorney Lake on the busiest day of the competition

London 2012 Olympic rowing organisers have warned spectators they risk sitting in queues during events they have paid to see.

The Olympic Delivery Authority (ODA) has confirmed more than 25,000 park and ride tickets for events at Eton Dorney Lake are still unsold.

On the busiest day, about 25,000 spectators are expected to visit the complex on the Berkshire-Buckinghamshire border.

Rowing and canoeing start from 28 July.

ODA transport director Hugh Sumner stressed ticket holders should take advantage of the remaining spaces as soon as possible.

He said: "If you leave it to the last minute, you risk being stuck in queues for longer than the events that you have paid to see."

The news came on the same day four-time Olympic gold medallist Sir Matthew Pinsent took a tour around the facility.

Flooded car parks

Eton Dorney Lake and Weymouth and Portland Sailing Academy in Dorset are the only two London 2012 venues where park-and-ride facilities are available.

The ODA also confirmed fewer than 27,000 park-and-ride tickets had been sold overall, with more than 285,000 still unsold.

Organisers have been forced to close one park and ride facility in Littlemoor Road, Weymouth, due to fears of flooding during the games.

But another near Radipole lake, which flooded earlier this month, will stay open and be used as a drop-off point only.

Any drivers who had bookings at the Littlemoor Road site will be transferred to another facility.