[Aliantha]

For one thing, if there were a huge influx of migrants in australia, legal or otherwise, there'd be nowhere for them to live. Already there are many families who have nowhere to live. Increasing the population without having time to build housing would be just plain stupid.

If people are living on the street or camping out or whatever, there'd be increases in crime for starters, and that's not the only problem.

Any socioligist will tell you that overcrowding in any species is likely to lead to tension between groups which obviously we already have enough of in the world.

No, allowing a huge influx of immigrants would be bad for any economy, not to mention the social structure of the community.