The Federal Government has confirmed it will pay thousands of young people as little as $300 a week to work on conservation projects as part of its so-called Green Army.

When it is fully rolled out, the Government expects 15,000 people aged between 17 and 24 will work up to 30 hours a week under the program.

Environment Minister Greg Hunt says they will be doing jobs such as stabilising sand dunes, building boardwalks and rehabilitating mangroves.

They will be paid between roughly $300 and $500 a week - less than the $620 weekly minimum wage.

"This is a significant increase on Newstart, it's a significant increase on Youth Allowance and it's a significant increase on Labor's green jobs corps," Mr Hunt said.

"It's a voluntary program. Young people who want to participate will learn about the environment, they'll be given a Certificate I or Certificate II and they'll also get work skills, training skills and create something permanent."

The trade union movement says the Government should not be paying the Green Army members rates below the minimum wage.

Australian Council of Trade Unions president Ged Kearney says the payment is too low and wants the workers protected by the country's workplace laws.

"This whole concept of the Green Army is the latest attempt by the Abbott Government to cut wages [and] cut conditions of working people in this country," she said.

"If these jobs actually exist, then they should be advertised; they should be structured so they are well-paid, safe jobs."

Mr Hunt introduced the legislation for the Green Army in Federal Parliament on Wednesday.

The program is one plank of the Coalition's "direct action" climate change policy, and is expected to cost $300 million over a four-year period.

The Federal Government has said training received will count towards qualifications in land management, park management, landscaping or horticulture.

Full-time projects will run for up to 26 weeks in groups of 10, with nine participants and a supervisor.