One of the most senior members of Australia’s workplace tribunal has been rebuked for sharing “politically controversial” comments on social media that attacked federal Labor leader Bill Shorten and the country’s largest construction union.

Fair Work senior deputy president Jonathan Hamberger. Credit:Sean Davey

The Construction, Forestry, Maritime, Mining and Energy Union had been fighting to get Fair Work Commission senior deputy president Jonathan Hamberger to recuse himself from a case last year over whether three CFMEU officials were “fit and proper” holders of work-site entry permits. Their request came after he shared an anti-union tweet posted by former federal employment minister Michaelia Cash.

After he declined to recuse himself, the union appealed to a Fair Work Commission full bench which on Thursday backed Mr Hamberger. The bench did, however, issue him a mild reproach, citing the need to stay out of political discussions.

The tweet, containing the headline “CFMEU notches up 100 members before the courts … A CENTURY OF SHAME”, featured a graphic of Mr Shorten dressed in cricket gear. It accused Labor of objecting to the restoration of the Howard-era Australian Building and Construction Commission (ABCC) with its tougher powers and penalties because the ALP receives “millions in donations” from the union.