Liberal MP Tim Wilson will be obliged to assess at least 97 parliamentary inquiry submissions containing text that he wrote himself.

Wilson is the chair of the House economics committee, which is currently conducting an inquiry into Labor’s proposal to end cash refunds for excess imputation credits.

However, Wilson has also created and authorised a campaign website, stoptheretirementtax.com, which he has been directing people to if they want to speak or register to attend inquiry hearings.

The website also allows people to make a submission to the inquiry with a suggested, pre-written submission against the Labor policy.

Guardian Australia has conducted an analysis of the 998 submissions on the inquiry website to identify which submissions contained this pre-written text, which Wilson would then have to consider in his role as chair of the committee.

Of the submissions that have been published, at least 97 contain some part of the text written by Wilson, while 92 contain almost all of the text. (Many of these contain extra information in addition to the pro forma text).

This figure will almost certainly increase as more submissions are made public. Currently the inquiry website covers submissions up to December, with those from January and February yet to be added.

When asked by Guardian Australia how he could assess submissions containing text that he himself had written, Wilson replied:“Australians choose to send in submissions because they agree with the content, and we should respect that decision. They are free to add their personal story, which should absolutely be considered as part of the inquiry.”

“If they send in a pro forma submission it is a statement they agree with and represents their view. As chair I must respect what people send in, not dismiss it.”

Wilson also suggested many more submissions had yet to be published.

“You are only seeing a small number of submissions. The secretariat has been overwhelmed at the response from the public and hasn’t been able to process them all,” he said.

But Labor used the analysis to renew a call on Wilson to resign. The Labor MP Matt Thistlethwaite said the reliance on pro forma submissions meant the committee’s final report would be relying on evidence written by its own chair.

“The pre-filled submissions from the Wilson website means significant portions of the submissions received by the committee are written by the chair of the committee himself,” he said. “When the committee writes its report, it will be relying in large part on evidence written by the chair.”

Q&A What are franking credits? Show A franking credit is an entitlement to a reduction in personal income tax payable to the Australian Taxation Office. The entitlement is offered to individuals who own shares in a company in recognition of the tax on profits paid by that company. It is attached to a dividend which the company pays to shareholders out of its after-tax profits. The value of the franking credit is equivalent to the tax paid on the individual’s share of the company profit before it was distributed as a dividend. The rationale for the credit is to avoid double taxation. Because the company has already paid tax on the dividend, the accompanying franking credit reduces tax payable by the individual on their total taxable income. If a company is paying the full 30% company tax rate, a “fully franked” dividend of 70 cents per share will be accompanied by a franking credit of 30 cents per share, representing the tax that the company has paid on its $1 per share of pre-tax profits. Franking credits are only available to Australian residents. Historically, the ATO did not refund individuals with cash for any franking credits in excess of their tax payable, but this was changed by the Howard government in 2000 to allow individuals to receive cash refunds even if they do not pay any personal income tax.

“Tim Wilson must resign as chair of the House economics committee. If he does not, the prime minister must finally show some leadership and sack him”

The inquiry into Labor’s franking credit policy has proved controversial, with Guardian Australia revealing that fund manager Geoff Wilson, an opponent of Labor’s policy, partly funded the campaign website. The same website uses the government coat of arms.

Tim Wilson is also distantly related to Geoff Wilson, and has shares in funds managed by Geoff Wilson’s Wilson Asset Management.

On Monday morning, Wilson appeared on Sky News to make a strident defence of his actions on the committee. He described Labor’s police complaint about possible privacy breaches as “complete rubbish” and a “grubby, pathetic, sad smear campaign”.

He rubbished suggestions of a conflict, either by his shareholding or distant relation to Geoff Wilson.

“Firstly the family connection, which people keep going on about; the person involved, Geoff Wilson, is my great grandfather’s cousin’s grandson,” he said. “You have to go back to the 1850s to draw this ridiculous connection. Yes, I hold shares that are managed by Wilson Asset Management. That was fully disclosed on the parliamentary register. It’s never been a secret.”

Tim Wilson also said he had done nothing wrong by using the coat of arms on his campaign website. It was “entirely consistent with the duties of a member of parliament to use the coat of arms as part of our parliamentary duties”, he said.

The “parliamentary purpose” was to “campaign against a piece of policy”.