THE design for the 2012 Olympic stadium will be unveiled today amid on-going concerns about costs and the venue's long-term future.

In October, Olympic Delivery Authority chairman, John Armitt, told the London Assembly that the £496m price for the 80,000-seater stadium had been agreed with main contractors, Robert McAlpine.

But it is understood that the figure was a forecast and the final total will not be known until the work is completed in 2011, a year before the London Games open.

Organisers hope to attract a tenant to move to the stadium, with a reduced capacity of 25,000, after the Games.

But League One club Leyton Orient said that was too big for their use while Premier League clubs have indicated it is too small.

The plans will be revealed at a ceremony in a marquee at the site in Stratford.

Work on the stadium is expected to start in May 2008, three months ahead of schedule.