PM plants tree in ice-cold Queanbeyan

Let no-one be in any doubt about the prime minister's commitment to the environment.

On a day when the wind chill factor plunged temperatures to minus 1.7 and snowflakes fell over parts of Canberra, Tony Abbott and his environment minister Greg Hunt ventured across the border into NSW for a spot of tree planting in pouring rain.

They were in Queanbeyan to meet participants in the government's Green Army, who "rain, hail or shine" are out restoring bushland and waterways, building tracks and eradicating weeds and feral animals.

The paid program for 17 to 24-year-olds who take part in the environmental restoration work has reached its fourth round of projects.

The next phase will have a special focus on heritage, rural, remote and indigenous communities, the Great Barrier Reef and threatened species, Mr Hunt said.

The $700 million signature program will be scaled up to 1500 projects and 15,000 participants.

"This is where our environmental credentials meet our economic credentials," Mr Abbott told reporters as they all huddled under a tiny marquee protecting them from the elements.

From trees, the focus immediately shifted to the seeds Mr Abbott sowed during a coalition party room meeting on Tuesday night that might or might not result in a popular vote on same-sex marriage.

The green shoots on that issue may still be a long way off.