Sports Minister John Sidoti has been referred to the Independent Commission Against Corruption following a fiery budget estimates hearing into his property investments.

Key points: The investigation will look into whether Mr Sidoti had access to confidential information that may have benefited his "personal interest"

The investigation will look into whether Mr Sidoti had access to confidential information that may have benefited his "personal interest" Mr Sidoti has been linked to decisions involving a property development in north-west Sydney

Mr Sidoti has been linked to decisions involving a property development in north-west Sydney NSW Labor said it it would refer Mr Sidoti to ICAC by the end of the day if Ms Berejiklian did not

Mr Sidoti's referral comes hours after NSW Premier Gladys Berejiklian called for an investigation into allegations involving the Sports Minister to help "restore the public's confidence" in the integrity of government.

Just an hour after Mr Sidoti finished giving evidence at a heated NSW budget estimates hearing — where he categorically denied any wrongdoing — Premier Gladys Berejiklian announced "a review into allegations" over his "disclosures and other obligations" as a Minister.

"I regard Mr Sidoti as a hardworking MP and Minister and note he has given strong assurances that he has acted appropriately at all times," she said today.

"I believe the Secretary's independent review is important to ensure there is ongoing public confidence in these matters."

Mr Sidoti has been linked to a $1,750 political donation the Liberal Party received from Chinese property developer Ming Shang in 2015 — a donation the Liberal Party handed back last night.

Mr Ming's firm is building $70 million worth of residential towers in Rouse Hill near the newly completed Metro West train line.

Mr Sidoti — who was Parliamentary Secretary of Planning at the time — has declared a 10 per cent interest in the Rouse Hill development through a family company called JAFS Investment Trust.

The Minster today faced fresh allegations over his role in the approval of an access road for the development.

Late on Thursday he was referred to ICAC by Greens MP David Shoebridge.

The $70 million Rouse Hill development in question. ( Supplied )

Mr Sidoti faced a grilling during budget estimates today, maintaining he was "a man of integrity".

"I have done nothing wrong," he said. "To suggest I had inside information is incorrect."

NSW Labor said it would refer Mr Sidoti to the Independent Commission Against Corruption (ICAC) by the end of the day if Ms Berejiklian did not.

Ms Berejiklian said she wanted to get to the bottom of whether Mr Sidoti had access to confidential information that may have benefited his personal interest.

"Donations are a matter for the NSW Liberal Party organisation and will not be the subject of this review," she said.

The Secretary of the Department of Premier and Cabinet will look into: