Queensland’s former housing minister Dr Bruce Flegg says he never recovered from alleged defamation at the hands of his sacked senior media adviser.

Allegations by a “vengeful” media adviser against former Queensland housing minister Dr Bruce Flegg have never been proved but devastated his political career, a court has heard.

Graeme Hallett, Dr Flegg’s former senior media advisor, summoned journalists to Queensland parliament a day after his dismissal in November 2012.

It was an “act of vengeance”, lawyer Nick Ferrett, acting for Dr Flegg in a defamation case, told the Brisbane Supreme Court on Wednesday.

“The purpose of that press conference, in the end, was to destroy Dr Flegg’s political career,” he said.

Mr Hallett accused Dr Flegg of lying to parliament by tabling a “grossly inaccurate, misleading” lobbyist register that failed to disclose interaction with his lobbyist son Jonathan.

Dr Flegg resigned the next day.

He told the court the allegations took an enormous toll.

“I was held up to public ridicule. That ridicule and media frenzy played through both the political world but also the constituents in my electorate. My own party members in some cases,” Dr Flegg testified.

“It was a blow I’ve never recovered from.”

The long-term MP said he knew he would be an “easy target” after Jonathan gained employment with consultancy firm Rowland before the 2012 Queensland election and gave ministerial staff specific instructions.

“I was really quite clear that I didn’t want Jonathan involved in any lobbying contact with our office and I think that was pretty widely understood.”

Mr Hallett also accused Dr Flegg of misrepresenting his whereabouts in his official diary, recording time spent practising as a GP in Morayfield, north of Brisbane, as having been spent in his Moggill electorate.

Dr Flegg repeatedly denied the allegation under cross-examination by Mr Hallet’s lawyer, Stephen Keim SC.

Dr Flegg was this month barred from contesting the 2015 Queensland election by Liberal National Party executives, a decision he said would have been unlikely if not for Mr Hallett’s “astonishing” media conference.

“It would be virtually unheard of to disendorse-endorse a minister,” he told the court.

Dr Flegg recalled being shunned by constituents in the aftermath of his resignation.

“It had a very severe impact in terms of stress, sleeplessness. I didn’t go out,” he said.

“It is the most horrible experience.”

The trial will also hear evidence from Jonathan Flegg and the executive assistant who was responsible for maintaining the lobbyist register.