A two-day 'festival of cycling' will be the first large scale event to use the Olympic Park when it reopens in 2013 after this year's Games, London mayor and keen pedaller Boris Johnson announced on Thursday.

Johnson said he wanted to create one of the world's leading cycling events in the capital as part of the legacy of the Games.

He pointed also to figures predicting the festival would attract more than 200,000 visitors to the capital and generate tens of millions of pounds in economic benefit.

This spectacular event will help ensure that the 2012 Games are just the start, not the end of the benefits of hosting the Olympics, Johnson, who faces a re-election battle in May against his old Labour foe Ken Livingstone, said in a statement.

We are already creating long lasting opportunities for the Park and the capital, which will showcase London to the world, attract more visitors, create more jobs and support the economy, added Johnson who was addressing business leaders later at the World Economic Forum in Davos.

London already has some 6,000 rental 'Boris Bikes' on its streets as part of a scheme launched by Johnson, a tousle-headed extrovert frequently photographed puffing around the capital on two wheels, in 2010.

Authorities say there has been a 15 percent increase in cycling over the last year alone and Britain's Olympic cyclists are tipped for glory again this summer after sweeping seven golds in Beijing four years ago.

Organisers plan the event to start with a family fun ride involving up to 70,000 cyclists on an eight mile loop of closed roads around London landmarks.

The next day would see up to 35,000 amateur, club and world class riders tackling a 100 mile course starting in the Olympic Park and heading into the southern county of Surrey along part of the 2012 Olympic road race course.

A tender process will be launched for potential bidders to become the commercial partner.

The Olympic Park Legacy Company (OPLC) also announced on Thursday that the park would reopen in phases from July next year when work is completed to return it to public use.

Through our advanced planning work we are able to be in a position to schedule the phased opening of the Park within a year of the 2012 Games finishing, said OPLC chair Margaret Ford.

This is a huge achievement given the scale of construction work that is needed following the closing ceremony and another example of how legacy plans for the Park are more advanced than any previous host Olympic city.

Part of the park is due to be transformed into a district with up to 11,000 new homes and commercial properties.

Friday marks six months to go until the Games begin with a spectacular opening ceremony at the new stadium in east London on July 27.

(Reporting by Alan Baldwin, editing by Ed Osmond)