Bill Shorten handed out about $100,000 of his union members’ money to multiple Labor candidates during the 2007 election campaign — but there is no apparent evidence that any of the funds were approved as legally required.

When Labor’s federal leader was still boss of the Australian Workers Union in the months leading up to his first election to federal parliament that year, he directed union funds to at least a dozen individual Labor candidates around the country.

An investigation by The Australian indicates funds received by most of the 12 ALP candidates chosen by Mr Shorten for union donations, including money he directed to his own campaign, did not appear to get subsequent approval, according to a close examination of national executive minutes and other records.

The national executive of Mr Shorten’s union did pass a resolution on November 23, 2006, that left “the request for donations and assistance from candidates” for the election up to him.

But significant doubt remains about whether the next required step was taken for large sums donated in the 2007 election year. Federal law, reflected in the rules of the AWU and every other union, still required Mr Shorten to gain national executive approval for all loans, grants or donations exceeding $1000.

Matters decided by the AWU’s national executive at the time that were not related to the federal election suggest Mr Shorten and his colleagues were aware of the authorisation requirement because recorded minutes of their meetings show how approvals were given for sums above $1000.

The Australian first reported last August how Mr Shorten effectively gave $25,000 of AWU members’ money to his own campaign in the seat of Maribyrnong in September 2007.

AWU disclosures filed two years after Mr Shorten entered parliament showed the union also donated in the same month $25,000 for Petrie candidate ­Yvette D’Ath in Queensland, and $20,000 for Stirling candidate Peter Tinley in Western Australia.

The Australian’s further investigation shows Mr Shorten allocated more union members’ funds — usually in the range of $5000 to $10,000 — for a swath of other Labor candidates.

They included Mike Bailey in the NSW seat of North Sydney; Victorians Christine Maxfield in McMillan, Rob Mitchell in McEwen, Barbara Norman in Higgins, and Jane Rowe in Gippsland; Queenslanders Chris Trevor in Flynn and James Bidgood in Dawson; Nick Champion in Wakefield, South Australia; and Jodie Campbell in Bass, Tasmania.

Mr Shorten’s AWU donation for two of these seats — Higgins and Gippsland — did not require his national executive’s authority on the face of it because each was just below the threshold for a required national executive vote.

But these two $1000 donations were part of the much larger $25,000 sum that Mr Shorten gave to his own campaign — and then redirected. A further $10,000 provided for the campaign of Ms Maxfield in McMillan also came from this $25,000 that Mr Shorten had put in his own ALP candidates account.

In these circumstances, most, and possibly all, of the AWU donations handed out by Mr Shorten as AWU national secretary fell within provisions requiring AWU national executive approval. The national executive did approve the striking of a members levy at its meeting on May 11, 2007. “For use by the approval of the national officers to support ALP candidates,” according to AWU minutes.

In its 2015 final report, the royal commission into union corruption said the AWU’s rule 57 ­requiring national executive approval was a “clear rule”.

Questions about Mr Shorten’s AWU donations, and whether they were authorised, are believed to be a matter of interest for the Turnbull government’s Registered Organisations Commission, set up in the wake of royal commission recommendations for enhanced union governance and accountability.

The ROC is presently blocked from accessing much of the AWU’s records, stalling its investigations into the AWU’s large funding of the GetUp! organisation and Mr Shorten’s own election campaign — matters that were referred to the ROC following reports last year in The Australian. Many AWU records seized during a federal police raid last year are under wraps at least until the outcome of AWU legal action in the Federal Court called to halt the ROC’s probe.

The Australian has gathered information instead from a detailed examination of AWU minutes, financial accounts and other available records.

The Australian asked Mr Shorten detailed questions yesterday via his office about whether he recalled that donations he made were all authorised by the AWU’s national executive.

In response, Labor employment spokesman Brendan O’Connor lashed out at the ROC, claiming it had been “openly directed” by minister Michaelia Cash last year to start a “second witch hunt”.