The chair of an inquiry ordered by Prime Minister Malcolm Turnbull amid the dual citizenship crisis says a constitutional provision banning millions of Australians from being elected to Parliament is broken and should be overturned at a referendum.

In her strongest comments on the issue to date, Liberal senator Linda Reynolds said it was her personal view that the only way to fix section 44 of the constitution - which ended the careers of eight MPs in an unprecedented eligibility fiasco last year and threatens the future of up to four more - was to take it to a referendum.

Her view raises the likelihood Parliament's joint standing committee on electoral matters will also recommend a referendum when it hands down its report shortly, setting up the possibility the vote could be held in conjunction with the next federal election.

Mr Turnbull asked the committee to investigate the dual citizen issue last year. At the time, Mr Turnbull said Australians wanted politicians to "resolve the citizenship issue once and for all" and said the inquiry will help ensure "future Parliaments" are not caught out.

Section 44 prevents any person who is "a subject or a citizen or entitled to the rights or privileges of a subject or a citizen of a foreign power" from running for office. It also bans anyone who has any direct or indirect pecuniary interest with the Commonwealth.