TWO Fair Work Australia probes into the Health Services Union were delayed by a flawed investigative process, a KPMG review has found.
FWA launched separate investigations into the HSU's Victoria No.1 branch and national office early in 2010.
Those investigations were instigated following initial inquiries lasting about a year.
The industrial watchdog was heavily criticised after both investigations took almost two years to complete.
KPMG was commissioned to conduct the review on the back of that criticism.
KPMG, which made 31 recommendations to improve FWA's investigative procedures, found both investigations were impeded by a lack of experienced, qualified investigators.
"The investigations by FWA were hampered by the absence of relevant investigation standards and procedures, document and case management protocols and insufficient appropriately-qualified and experienced personnel," a statement issued by FWA late on Tuesday read.
"These issues almost certainly contributed to the time taken to complete the investigations."
The release of the KPMG review came as Terry Nassios, the man who led FWA's investigation in the HSU national office, was preparing to front the Electoral Matters Committee in Canberra.
Mr Nassios last appeared before the committee, which is reviewing the Australian Electoral Commission's analysis of the FWA report, in July.