Work on London's Olympic Stadium completed.

The last piece of turf was laid Tuesday at the Olympic Stadium, symbolizing the completion of construction on the 80,000-seat flagship venue for the 2012 London Games.

The stadium will host the Olympic track and field competition and the opening and closing ceremonies. Former Olympic sprinter Frank Fredericks used a shovel to lay down the last piece of grass on the infield, 16 months before the start of the games.

Construction of the stadium, which cost $777 million, began in May 2008.

"The Olympic Stadium has been finished on time and under budget," Olympic Delivery Authority chairman John Armitt said.

London organizers and International Olympic Committee officials visited the stadium to mark the milestone.

Fredericks was among the members of the IOC coordination commission taking part in the ceremony at the Olympic Park in east London. The IOC panel is making its eighth visit to London to check on preparations for the games.

A total of 360 rolls of turf were needed to cover the 97,000-square foot infield. The surface of the running track will be laid later this year.

"We wouldn't want anyone to run away with the idea that this stadium is ready to stage an Olympic track and field championship tomorrow," organizing committee chairman Sebastian Coe said. "With one year and a few months to go, this is a great place to be."

After the games, the stadium will be converted to a 60,000-seat venue that will serve as home to West Ham soccer club. The arena also will host track and field competitions, concerts and community events.