Alun Ffred Jones, leader of Gwynedd council, said considerable effort had been put in to ensure that local labour was employed on the recently completed Llanllyfni bypass in north Wales.
He said: "The Welsh Development Agency is working on sourcing contracts in Wales, and building up supply chains, which should mean the employment of local workers."
He said Cardiff University had carried out research to take advantage of clauses in European legislation that stipulated that some degree of locally supplied goods and services could be insisted on.
I don’t want to see English workers commuting in when they build the M4 junction at Llanilid
Alun Cairns, Conservative spokesperson
Davies said the assembly was testing to what extent these "social clauses" can be used within public sector construction contracts to encourage the employment of local people.
He pointed out that Brussels allows contracts to be awarded on the basis of the most "economically advantageous" tender, for which the criteria can be broadly defined. Procurement criteria could include sustainable development and the consideration of community interests, which could lead to local unemployed people being given work.