The key employer group for builders in Victoria relies on multimillion-dollar grants from the CFMEU’s redundancy fund to stay afloat, creating potential conflicts of interest for its bargaining with the union and for large bonus policies for senior executives, a whistleblower complaint alleges.

The Fair Work Commission is inquiring into claims by three directors of the Master Builders Association of Victoria that it is only profitable due to grants from the CFMEU’s $1.2 billion Incolink fund, sources familiar with the investigation said.