Prime Minister Scott Morrison says the Liberals are "doing the due diligence" after the party lost three candidates in Victoria because of their eligibility to sit in parliament.
Section 44 has claimed its first victims from a potential new parliament with the trio withdrawing from the race.
Kate Oski, the candidate for Lalor, and Vaishali Ghosh, the candidate for Wills have pulled out over dual citizenship issues.
Meanwhile, Helen Jackson, the candidate for Cooper is likely to be dumped because she is an employee of Australia Post.
Mr Morrison told a press conference that Section 44 was still "complicated", but said the three candidates were not running in "highly contested seats".
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"What this demonstrates is just the party doing its job," he told reporters in Sydney.
"They identified the problem and they fixed it. And I'm pleased they have done it before the close of rolls."
Bill Shorten said the Labor party had policies in place to prevent a repeat of the citizenship saga.
"I can guarantee my party is doing everything it can to eliminate any doubt about constitutional requirements," he told reporters on the NSW Central Coast.
Speaking in Melbourne, Greens leader Richard Di Natale also said the party had done what they could to ensure their candidates "go through a very thorough process to make sure they're eligible to stand".
This is the first election in which candidates are required by the Australian Electoral Commission to submit a qualification checklist relating to section 44 of the Constitution after the 45th parliament was plagued by disqualification issues.
