The Marriage Amendment Bill's final hurdle has been passed with the Governor-General this morning signing it into assent.

Sir Peter Cosgrove gave the laws royal assent on Friday morning when he was visited by Prime Minister Malcolm Turnbull and Attorney-General George Brandis in Canberra.

"It is now part of Australian law," an elated Mr Turnbull said.

The bill being presented to Sir Peter Cosgrove (AAP)

The bill being given royal assent (AAP)

It comes as many Australians celebrated well into the night to mark the significant day in the country's history.

There were cheers and applause from a packed public gallery, which led a chorus of 'We Are Australian', after members of the lower house voted in favour of the bill.

Four members voted against the bill.

A jubilant Prime Minister Malcolm Turnbull said it was "time for more marriages, more equality, more love".

"What a day for love, for equality, for respect," Mr Turnbull told the house.

He followed up that sentiment this morning on TODAY, adding: "What a great day for love, for respect, for equality. What a great Australian day."

"The nation had spoken overwhelmingly for marriage equality and the parliament voted overwhelmingly for marriage equality. It's one of those remarkable moments in our history."

"A discrimination brought to an end after many years of debate... in a way that unites the nation."

Liberal MP Warren Entsch lifts up Labor MP Linda Burney as they celebrate the passing of the bill. (AAP) (AAP)

Veteran Liberal MP Warren Entsch hugs the prime minister. (AAP) (AAP)

Crossbenchers Cathy McGowan, Adam Brandt and Andrew Wilkie wave a flag to celebrate the passing. (AAP) (AAP)

Opposition Leader Bill Shorten said the legislation's passage is a unifying moment for the nation.

"When this bill is passed, we should declare we are no longer a nation who voted no or yes - we are simply Australians all," Mr Shorten said.

"Equality is never a gift to be given."

"The right to marry in Australia will no longer be determined by sex or gender. Marriage will now be defined in the Marriage Act 1961 as the 'union of two people to the exclusion of all others, voluntarily entered into for life'," Attorney-General George Brandis said.

"Same-sex couples will now have the same rights under the Marriage Act as all other couples."

The isolated 'No' can be seen on the left side of the chamber (Getty)

The chamber was upstanding as the bill passed. (9NEWS)

From this Saturday, same-sex couples will be able to lodge a Notice of Intended Marriage, kicking off the one-month minimum notice required before the performance of marriage under the Marriage Act.

The first gay weddings will be held just a few days into the new year.

Marriage equality advocate Ian Thorpe thanked the Parliament for the "surprising" passing.

"Today really is a momentous day for Australia and today I am proud to call myself an Australian, as much as I have any other day of my life," he said yesterday.

The members voting yes on in the House of Representatives. (AAP) (AAP)

"I realise what this means for young LGBTQI people, right across the country, for them to know that the person they love, the way they feel, is equal to that of anyone else, and the chance that will mean for future generations is significant.

"I would like to thank both sides of politics for getting on with the day and doing what they said they would do. I am surprised, frankly."

The House of Representatives shot down all the amendments proposed by seven MPs after the legislation passed untouched through the Senate last week, ending a marathon campaign.

The public gallery applauded as each amendment was knocked back.

"These amendments are totally unnecessary. This is a marriage bill, this is not the time to be changing the charities act or the income tax assessment act," veteran Liberal MP Warren Entsch said, shutting down an amendment proposed by Andrew Broad.

"This bill already strikes the right balance. The Senate voted for it and so should we.

"Australians have waited long enough for marriage equality. We can deliver it today. Let's get it done."

More than 120 MPs spoke during nearly 24 hours of debate on the bill, which was sponsored by gay Liberal Senator Dean Smith and backed by colleagues Warren Entsch, Trent Zimmerman, Tim Wilson and Trevor Evans.

Former prime minister Tony Abbott tried to effectively kill off the legislation with an amendment that would stop its progress, but failed.

Tens of thousands had been prepared to celebrate the historic moment, with celebrations starting early.

Dozens gathered for a marriage equality rally and were seen singing and dancing on the lawns of Parliament House.

Actress and same-sex marriage campaigner Magda Szubanski addressed the crowd, saying it would be an emotional day.