Queensland's corruption watchdog will proceed with "further inquires" into the Premier's former chief of staff David Barbagallo, over a State Government investment worth hundreds of thousands of dollars into a company he part owned.

Key points: A company part owned by David Barbagallo received an Advance Queensland Business Development Fund investment worth $267,000

A company part owned by David Barbagallo received an Advance Queensland Business Development Fund investment worth $267,000 The State Opposition referred the matter to Queensland's Crime and Corruption Commission

The State Opposition referred the matter to Queensland's Crime and Corruption Commission In a statement, the CCC today said it had reviewed that report and that it would need to make further enquiries

It comes less than a month after he stepped down from the top role.

In September, Premier Annastacia Palaszczuk said Mr Barbagallo told her of his intentions to retire in June, several weeks before revelations of the investment were made public during Queensland Parliament's budget estimates hearings.

At the time, it was revealed a company part owned by Mr Barbagallo — known as Fortress Capstone Pty Ltd — received an Advance Queensland Business Development Fund investment worth $267,000 to go towards the development of the 'CruiseTrakka' smartphone app.

Ms Palaszczuk told Parliament she had been told about the Government investment in the company and ordered private company Ernst and Young to conduct an internal investigation into the investment after it was made public.

The State Opposition referred the matter to the Crime and Corruption Commission (CCC).

In a statement, the CCC today said it had reviewed that report and it would need to make further enquiries.

"The CCC has considered the review report obtained by the Department of the Premier and Cabinet (through an external company) with respect to the grant allocation process and how it related to Fortress Capstone Pty Ltd," the CCC statement said.

"The CCC considers that further enquiries need to be made in relation to the matter.

"The CCC does not intend to comment further until it has finished dealing with the matter."

Deputy Opposition Leader Tim Mander called on the Premier's office to release the Ernst and Young report to the public.

David Barbagallo at estimate hearings at Queensland Parliament on July 23. ( AAP: Jono Searle )

"Annastacia Palaszczuk should release the report that she has funded under taxpayers' money to the public," Mr Mander said.

"There is no reason why that report should not be made public today."

Mr Mander said he believed it was not best practice for senior staff to be linked to State Government investments.

"I don't believe that it's an appropriate investment to go to a Government staffer at that level — there's a perceived conflict of interest," he said.