LONDON - Omega extended its Olympic sponsorship Tuesday to become the official timekeeper of the 2012 London Games in a deal worth more than $70 million.

A saleswoman shows off brands beloning to Swiss Swatch Group in a watch and jewellery shop in Zurich. [Reuters]

The Swiss watchmaker was a sponsor of the Turin Olympics, and had already committed to the 2008 Summer Games in Beijing and 2010 Winter Games in Vancouver.

The contract was signed in London by International Olympic Committee president Jacques Rogge and Nick Hayek, chief executive of the Swatch Group, which includes Omega.

Omega becomes the sixth company in the IOC's global sponsorship program for 2010 and 2012, joining Coca-Cola, Atos Origin, General Electric, McDonald's and Visa. Sponsorships sell for $70 million or more.

Rogge said it's the first time 60 percent of the sponsors have been lined up six years ahead of the games.

IOC marketing chairman Gerhard Heiberg said the committee plans to have 10-to-12 sponsors for the 2010-12 period. The IOC has 12 international sponsors for 2006-08, generating $866 million in revenues for the Olympics. The IOC hopes to break the $1 billion figure in sponsorships for Vancouver and London.

Omega's Olympic ties go back to the 1932 Los Angeles Games. Coke, an Olympic sponsor since 1928, extended its relationship last August through 2020.

Meanwhile, London officials said the cost of staging the 2012 Olympics would be $3.7 billion, higher than the previous estimate of $2.8 billion.

Sports Minister Richard Caborn told Parliament the earlier figure did not include inflation.

The organizing committee said all 2012 candidate cities had been told by the IOC to put the estimated budget figures in 2004 prices when bidding for the games.