Federal Court officials have found a number of missing files at the centre of the Australian Workers Union slush fund scandal - but confirmed others have disappeared.
Deputy Opposition Leader Julie Bishop had urged police intervention unless Queensland court records relating to a bid in the mid-1990s to recover money from the disgraced former boyfriend of Prime Minister Julia Gillard and his associates were quickly found.
A Federal Court spokesman said an exhaustive search had discovered the missing Queensland files in the court's Victorian registry in Melbourne on Monday.
But he confirmed that a box of records was still missing from the court's NSW registry, including a crucial affidavit and supporting documents assembled by AWU whistleblower and now Fair Work Australia commissioner Ian Cambridge.
Former industrial lawyer Harry Nowicki said the NSW documents, which were missing when he visited Sydney in September, were believed to include the original copy of a Slater & Gordon conveyancing file for the 1993 purchase of a Fitzroy unit with more than $100,000 stolen from the AWU Workplace Reform Association.
The property was purchased by AWU official Bruce Wilson, Ms Gillard's then boyfriend, in the name of union crony Ralph Blewitt, who had never seen the unit. Ms Gillard has repeatedly denied any wrongdoing.
Slater & Gordon confirmed last month it could not locate an unofficial file prepared by Ms Gillard when she was a partner at the firm in the early 1990s and advised on the incorporation of the Workplace Reform Association.
It was later confirmed that a file in the West Australian state archives relating to the incorporation was empty.
Ms Bishop said it ''beggared belief'' that documents held in government and court archives could disappear.
The Federal Court spokesman said the recovered files - containing documents lodged with the Queensland Industrial Court registry in 1995 by former AWU national president Bill Ludwig - had gone missing after being sent to Melbourne earlier this year.
''These particular files were kept in off-site archives in Brisbane but, over time, were sent to Sydney and Melbourne to accommodate searches by journalists and others,'' he said.
''The files were retained in Melbourne in anticipation of further search requests but unfortunately their whereabouts was not entered on to the system established to track them.''
He confirmed the search for the missing NSW registry records was continuing
Mr Nowicki, who has been privately researching the AWU scandal, said the NSW files - coded NI2082 - relate to a legal action subsquent to the Ludwig proceedings initiated by Mr Cambridge in 1996 after the discovery of the rorting of the Workplace Reform Association. Police investigations confirmed more than $400,000 was stolen from the association by Mr Wilson and his associates.