He accused Labour MP Pete Hodgson of "an incredible abuse of parliamentary privilege" and said his suggestion would be defamatory if he repeated it outside Parliament.
Dr Worth said he had led three non-profit business councils promoting trade "and I have always paid my own way".
Dr Worth resigned from New Zealand Aviation on Monday, and yesterday resigned as director from two more companies.
One of them, the Indian Overseas Group Ltd, had three National MPs as directors - Trade Minister Tim Groser, list MP Kanwal Jit Singh Bakshi and Dr Worth.
The three are believed to still be shareholders pending the company's removal from the companies register.
Mr Groser said last night he just discovered he still held 2000 shares in Indian Overseas Group Ltd. He resigned from the company in February to avoid any possibility of conflict of interest.
He said last night he made the discovery after checking the companies register following a media call, NZPA reported.
Dr Worth said last night he had resigned directorships he held with all companies.
As is required for ministers, Dr Worth received Prime Minister John Key's approval for the private overseas trip.
But he did not declare he was a director of New Zealand Aviation, which is in a joint venture with an Invercargill flying academy and which secured a flight training deal in India.
Dr Worth was also quoted in Indian media as promoting New Zealand for its flight training skills.
Labour leader Phil Goff in Parliament yesterday described the trip as a "private business junket". Mr Key deflated his attack by declaring that one of the honorary advisers to the the India Trade Group was Mr Goff himself.
But Mr Hodgson led the more scandalous allegations: "Were his fellow shareholders in New Zealand Aviation . . . amongst those who contributed $1000 per person towards his personal expenses? If so, just how much did the trip to India cost him, or might he have run it at a small but tidy profit?"
Dr Worth said in Parliament: "I am simply unaware of the truth of that statement. I do not believe it to be correct."
