Some names appear to have signed the online petition up to eight times.

Software had detected a "large number of irregularities" in an online petition opposing abortion law reform, Speaker Curtis Pitt said.

The petition has 23,886 signatures opposing the "government's extreme abortion" bill.

About 3000 signatures were identified as duplicates and were removed from the total, leaving 23,886 names.

Mr Pitt said Parliament clerk Neil Laurie had advised about 10 per cent of people who joined the petition had "duplicated their joining".

"Indeed, it appears that some petitioners have joined the petition up to eight times," he said.

Under parliamentary rules, people are only allowed to sign petitions once.

"Other petitioners have not provided their relevant address details as required by standing orders," he said.

"There are also grounds to suspect that some of the details provided are not true details and thus may be fraudulent."

Mr Pitt said the presentation of the petition may be delayed while the clerk and officers investigated.

Australian Christian Lobby Queensland director Wendy Francis, the principal petitioner, said the Parliament's online petition system was chosen because it was very rigorous.

"We are very confident that it is a really good process and people can't actually be counted twice," she said.

Ms Francis said some people may have signed the petition more than once in confusion because they were not sure whether they had signed it previously, as there were also petitions against the two previous abortion law reform bills which were introduced - and later withdrawn in 2017 - by independent MP Rob Pyne.

"That is why I use this system because it is so good in finding out whether people have signed it twice," she said.

"If we'd done a change.org petition, we could have got hundreds of thousands of people to sign. In a change.org petition, people can put lots of different email addresses or anything.

"We use it [the Parliament's e-petition] because it's such a good system and it finds out whether people have signed twice, whether purposefully or, most likely, accidentally."

Ms Francis said there were more than 37,000 signatures in total on the petition, including names on a paper petition, and she understood it would be introduced into Parliament on Thursday.

Petitions with 10,000 signatures or more can be debated by MPs in the Parliament.

A parliamentary committee considering the Termination of Pregnancy Bill is due to report by October 5.

Ms Francis said the committee, given only one month to consider public submissions, should have been given more time.