Pressure is mounting on the Greens over their contentious deal with the Government on Senate voting reform, and over talk of a preference swap with the Liberal Party at the coming election.

The heat will be on in the Senate today, when Labor and the crossbenchers will use every procedural opportunity to stymie debate on the voting changes.

That includes a push by David Leyonhjelm to try and wedge the Greens by bringing on a vote on their very own Bill for marriage equality.

Greens Leader Richard Di Natale joins Fran Kelly on RN Breakfast.