Perhaps by stating 'internationally recognised' they mean 'at least to certificate level'.
I did a basic TESOL course with a company called
Teach International and they are fantastic. The initial one week course must be done in Australia, NZ or Canada before you go and then you have three months to do an online component.
This basic course I did can be upgraded to Cert III or Cert IV with supervised observation and practise teaching (both can be done before you go or overseas) and some extra online components.
Most serious employers here in Hong Kong (who pay decent salaries and offer good conditions) will require a TESOL to certificate level.
If you intend to teach ESL back home, in Australia for example, you are required to have Cert IV level TESOL certification.