He said: 'We're looking at building clauses into contracts as far as legally possible for contractors to build sites using local labour.'
But one delegate questioned whether the call for local labour was feasible against a backdrop of industry skills shortages.
He said: 'With the amount of work that has to be done and the shortfall of skills, do you think the local labour principle has to be compromised?'
Mr Lewis said: 'We hope not. We are going to be working with the Learning and Skills Council but we have a three-year window in which to look at it. The aim is to maximise benefits for local people.
'There may be higher technical jobs that only certain people can do, but local labour is the aspiration. There will be construction labour coming back to the market after the completion of jobs like Wembley and the Channel Tunnel Rail Link. We are just beginning to map the demands in detail.'
He said the Strategic Forum's Olympic Task Group would also build on early London Development Agency initiatives such as a construction academy, increased vocational training and establishing an
Olympic 'job shop'.
The LDA said the construction academy would be a 'virtual academy'. A spokeswoman said: 'A consultant prepared a feasibility study on an Olympic skills academy, but it was decided we didn't want a shiny new building.
'It will take the form of an online academy with more joined-up thinking between training organisations. It is too early to say what funding levels will be.'
The GLA is also planning a programme of business support to advise companies on how to tender for major contracts, as well as supply chain initiatives such as 'meet the buyer' events.