About 30,000 people are expected to work on the Olympic site by 2012
A union will demonstrate outside the 2012 Olympic Games site to demand more jobs are offered to local workers.
Members of the GMB union also want construction workers at the Stratford, east London, site to be employed directly rather than through agencies.
Spokesman Tom Kelly said the 6 May protest will ask for "well-paid good jobs" for the local community.
The Olympic Delivery Authority (ODA) said around a quarter of the 3,500 workers on the 2012 site lived nearby.
In January Prime Minister Gordon Brown hailed the Games as a "job creator" and said about 30,000 people will have worked on the Olympic site by 2012.
But GMB official Mr Kelly said all construction workers on the site should receive rights under the Pay As You Earn (PAYE) tax system, rather than working through employment agencies.
"Direct employment on PAYE on agreed rates and conditions is the key that will open the door to the well-paid good jobs promised to the local community in east London," Mr Kelly said.
An ODA spokesman said that around a quarter of site workers lived near the Stratford site and around half lived somewhere in London.
The workforce would increase to 10,000 by 2010 as the pace of building work accelerated, he added.
"Local people are given priority in accessing training and jobs onsite through local job brokerage services in the local area," the ODA spokesman said.
"There are high levels of direct employment on the site and an agreement with construction unions includes recognition of national working rule agreements, training and local employment."