Warren Entsch's same-sex political rainbow

Warren Entsch's same-sex marriage bill has created a rare political rainbow.

A tight group of MPs from all parties gathered around the Liberal MP as he introduced his cross-party bill to federal parliament on Monday.

The group, largely Queenslanders like Mr Entsch, joined forces on the government side of the chamber about 10 minutes before he started speaking.

From the Liberal-National Party were Teresa Gambaro and Wyatt Roy, plus the Northern Territory's Natasha Griggs.

Labor MPs crossing the floor were Wayne Swan, Laurie Ferguson, Graham Perrett and Tim Watt.

Rounding out the group were independents Andrew Wilkie and Cathy McGowan and Adam Bandt from the Greens.

Queensland Labor MP Terri Butler, the bill's seconder, went across to Mr Entsch before he started speaking and hugged him warmly before returning to her normal place.

Almost every other Labor MP was in the chamber for Mr Entsch's 10-minute speech.

The government benches were more sparsely populated, though senior ministers Malcolm Turnbull and Christopher Pyne came.

At the end, Labor MPs clapped and some crossed to congratulate Mr Entsch.

However, the public galleries were almost empty and - apart from a couple of tentative claps at the end - silent.