GREATER Western Sydney football boss Jason McCartney is under investigation by the AFL after unleashing a 'tirade' at the umpires at half-time of Friday night's clash against the Western Bulldogs.

Witnesses to the incident have said that McCartney burst into the umpires' rooms at the break to approach them about what he perceived as incorrect decisions for the Giants during the first half of the club's 39-point loss at Manuka Oval.

The 47-year-old is expected to be issued with a 'please explain' from the AFL within the next 24 hours.

The Bulldogs led the free kick count 11-3 at half-time and led the match by just eight points.

By the end of the game the free kick count was 15-16 in favour of the Dogs as they blew the game apart with a nine goal final term.