Immigrant Impact on Economy

I'm really intrigued with this quote from Tim Wood, a legal South African immigrant:

"There is concerted effort led from all branches of government to ensure that wage prices at the lower end of the market do not rise and they do that by allowing the importation of vast quantities of illegal immigrants who suppress what would otherwise be a market price."

I think that there may really be merit to this argument. When discussing this particular facet of the illegal immigration issue, I think it's important to remember that the guv'mint itself is a consumer of such labor. For example, the state hires contractors to do construction projects such as road work to keep costs down. The contractors then hire illegal immigrants, largely to keep costs down and remain competitive in the low-bid game.