A Senate Committee has directed the Criminal Justice Commission to justify closing down its investigation into why state cabinet authorised the destruction of highly-sensitive inquiry documents in 1990.

In March 1990, cabinet authorised the shredding of documents accumulated by the so-called Heiner Inquiry, a 1989 investigation into the John Oxley Youth Centre, conducted by retired stipendiary magistrate, Noel Heiner.

The documents were shredded after being sought for court proceedings by solicitors for Mr Peter Coyne, the centre's acting-director who was removed from the John Oxley Youth Centre shortly after the inquiry was prematurely ended by Family Services minister Anne Warner.

Coyne had claimed his removal as acting-director had resulted from the defunct inquiry, a claim rejected by Ms Warner who said the decision to remove Coyne was taken independently.

The shredding also coincided with the dismissal of Mr Kevin Lindeberg, a public service union Industrial Officer representing Coyne who had clashed with Ms Warner's staff over the impending shredding. In May 1990 the Queensland Professional Officers' Association sacked Lindeberg, citing his relationship with Ms Warner as one reason for his dismissal.

So far the CJC has held two investigations into the shredding: the second took place after the commission discovered innacuracies in its first. The CJC has since apologised to Lindeberg over this. Neither investigation, however, found anything untoward.

Earlier this month, Mr Lindeberg addressed a Brisbane hearing of the Senate Select Committee on Public Interest Whistleblowing . He claimed a political connection between a CJC investigator and the Goss Government.

"The last investigation was carried out by a barrister with known ALP connections and connections to the Queensland premier," Mr Lindeberg said.

Mr Lindeberg said the investigator had "phoned my home, abused me, and attempted to intimidate me". "I complained to the CJC about this unsolicited call, but it did nothing," he said.

Documents were tabled at the hearing indicating Mr Goss had worked together with the investigator on the management committee of the Caxton Street Legal Service in the early 1980s - Mr Goss was President, the now- investigator was the service's Legal Co-ordinator.

In response, the head of the CJC's Misconduct Division, Mr Mark Le Grande, said he knew the case had "a long history", but said he could not speak "off the top of my head without access to the files".

The committee's acting chair, Senator Christabel Chamarette, told Mr Le Grande "in light of submission you have given us, we will want to recall you for some further questions on that".

Mr Le Grande said he would prepare a response for the committee.