Check out Queensland Building Services Authority website
some contractors (based on $) will require a contract.
http://www.bsa.qld.gov.au
they will have some tips as well as a licence search
so you can view a licenced tradies records
hope that helps

I have just finished building with Dixon at Yamanto in Brisbane’s west.
We had a very easy time keeping track of the home & what was happening,
by using the web based login & It was easy make comment on any concerns we had.
They built in 14 weeks. We rented the home within 2 weeks
with a cash positive return. Would not hesitate to use them again.