The person giving the endorsement usually must hold a current instructor rating with META, a type endorsement and 10 hours Comand on type.
In addition, as a general rule, they must be working for a flying school that also has those types on the AOC.
A Grade 1 Instructor with META may conduct the endorsement without a flying school, as a private operation, but this is dependant on the personal veiws of the local CASA FOI's and the instructors willingness to sign you off without the legal/insurance backing of working under an AOC.
Also Check captains working under a CAR 217 organisation may have the privleges without having an instructor rating.
And lastly independent ATO's or CASA FOI's may aswell.
I dont think I have missed anyone. for more info see CAO part 40, CAR 5.23 and the 'Flight Crew Licensing Procedures Manual' (its on the CASA website)
Hope this helps
Ted