In my experience working at a 'State' school requires no qualifications whatsoever but they usually would like you to have some experience working in a school of some description, of course some ask for a degree and a TEFL certificate which is often deemed a bonus but a teacher's license is not a requirement, hence the lack of a demand for certification.
State schools in general do not have the funding to hire well qualified teachers, although some of course do, but that it is up to the teacher to take a lower than average salary, however. State schools seem to get things done somewhat easier in terms of visa, WP etc. and of course can be a lot of fun and even, dare I say it, quite professional and well-run establishments.
However, any form of private establishment requires all the necessary certification and all the hoops to be jumped through, its when you go through the hoops that the fun and games begin and it is usually the private establishment that is at fault, this board is testament to the vagaries of that challenge.