Speaking at the London 2012 Volunteering Summit, Justin Davis-Smith said 80 volunteering organisations - representing most of the UK's 23 million volunteers - have pledged to provide volunteers in support of London's Olympic bid.
The aim is to recruit 25,000 volunteers by 2008 and the rest of the 70,000 by early 2012.
Volunteers would be recruited in sports clubs, local volunteer centres and community associations to carry out tasks ranging from ushering to medical care and first aid. After the games, they would be encouraged to use the skills gained to get employment or take up educational opportunities.
"We will not only create a volunteer programme that is second to none in 2012, but we will also leave a volunteering legacy that will benefit communities in this country and, through exchanges, many overseas countries for years to come," said Richard Sumray, chair of the London 2012 Forum.
Meanwhile, Volunteer to Win, an initiative established by the London 2012 campaign, has handed out £38,000 in grants to projects and individuals as part of its campaign to enlist community support for the Olympic bid.
"In total, £33,000 was made available to voluntary and community organisations in London - up to £1,000 each - for activities to support the Olympic bid, and an extra £5,000 for five individuals to share," said Araba Webber, project manager for Volunteer to Win.
Each proposed project had to be based in London and involve the community and volunteers in an activity that demonstrates local community backing for the Olympic Games.
"It's to show there is local community support in London for the Olympic bid. It's important for the International Olympic Committee to see that there is wider public support for the Olympic bid as well," Webber said.
The winners of the grants were unveiled at the launch of the Kingston Games, which won £1,000 from Volunteer to Win. Other winning events include an art exhibition at Wimbledon station and training volunteers to teach children slalom canoeing in Barking.
The group also called for registrations from people interested in volunteering in their communities. It has received more than 11,000 registrations since it was launched in December.
Those who register receive a pack telling them about local volunteering opportunities. If London does get to host the 2012 games, they will be told how to volunteer for the event.
- See News in focus, page 20.