But the LRAA said it would make it impossible for females to retain the right to female-only or lesbian-only spaces, services and provisions because any male could simply declare he was female and have every legal right to use them.
"At present, New Zealand law requires a burden of proof in order to change legal sex. There is a Family Court process to ensure abusers do not take advantage of the system. A shift to simply filling out a statutory declaration form to change sex with no oversight shows a blatant disregard for women's human rights," the alliance said.
"This move risks the safety of women in prisons, the continuation of women-only and lesbian-only organisations, and ultimately renders the sex discrimination protections in the Human Rights Act meaningless."
Family First also objected to the planned changes, saying historical documents should not be allowed to be manipulated by the state or politicians.
National director Bob McCoskrie said politicians wanted to ignore biological reality and, in the process, bring about confusion and ambiguity.
"A birth certificate is a historical record based on fact, not a political tool to further an ideology.
"By choosing you own gender in your birth certificate, the certificates will become an object of unscientific gender ideology and effectively tell medical professionals that they got it wrong at the time of birth."
The changes would render birth certificates meaningless.
Hudson said the original birth certificate would not be erased under the changes. The public record might change but the original details would still be kept.
But the select committee had made some effort to assess what harm such a change would create for others and it determined to a high level of confidence that it would not place others at risk.
The committee recommended changes in the birth certificate for a 16- or 17-year-old require the consent of their guardian and a recommendation of a health professional.
Under another change, the committee recommended that when a child's birth was registered, the parents be allowed to choose their status as "mother", "father" or "parent".
The bill, which was last modernised in 1995, was introduced by former Internal Affairs minister Peter Dunne but has been taken over by his successor Tracey Martin.
Assuming Martin has the support of her New Zealand First caucus, the changes look set to get the unanimous support of Parliament.