The Relationship Properties Act now covers each partner's right to divide relationship property and allowed the property to be in the names of both partners.
The report from the Law Commission found the only advantages left in the Joint Family Homes Act 1964 were protection from creditors and some minor advantages in relation to legal costs.
It found the number of people registering joint family homes under the act had dropped from 30,000 in 1974 to just over 1,500 in 2001.
Mr O'Connor said the National Party was committed to reducing unnecessary legislation.
"There is a wider philosophy within this - that's to make legislation that's accessible, legislation that's clear, concise, up-to-date, non-repetitive and current."
He said the original act was set up to protect the family home when the husband or wife went bankrupt so that the house could not be lost.
"It only protected the equity of the house, or up to $103,000," he said.
This is now covered under the Relationship Property Act 1976.
Labour MP Charles Chauvel said the legislation discriminated against single owners and couples in de facto relationships, and the protection it provided against creditors was limited.
"The Labour Opposition will be delighted to support it to select committee and we will listen to the evidence carefully," he said.
Green Party housing spokeswoman Holly Walker said the act was discriminatory on the basis of marital status.
"There has been a trend away from formal legal marriage towards de facto relationships which have since been recognised in law. This 1964 legislation has never been updated to take into account the change in law allowing civil unions," she said.
The bill received unanimous support during its first reading in Parliament.
