Former federal minister Bruce Billson has been cleared of breaching ministerial and lobbying rules.
Prime Minister Malcolm Turnbull on Monday tabled a letter from the secretary of his department, Martin Parkinson, which came after an investigation into whether the former small business minister had lobbied ministers within 18 months of leaving the job.
"On the basis of the information provided to me I have no reason to conclude Mr Billson has breached either the statement of ministerial standards or the lobbying code of conduct," Dr Parkinson wrote in the September 4 letter.
Mr Billson had assured him "he both understands and has complied with his post-ministerial obligations under the standards".
"Mr Billson has also assured me that he understands the requirements of the Australian government lobbying code of conduct."
Mr Turnbull told parliament Dr Parkinson had not interviewed any ministers during the investigation.
Mr Billson is executive chairman of the Franchise Council of Australia, which lobbied the government in favour of workplace law changes.
Mr Billson's activities are also being examined by the parliament's privileges committee.
The committee is looking at whether by being a paid director of the Franchise Council of Australia while still a member of parliament constituted a contempt of parliament or inappropriate conduct.
The tabling of the letter came after it was leaked to the ABC.
Labor questioned the value of an investigation that did not include questioning ministers who may have been lobbied.
