The Green Party is trying to woo the student vote by promising free public transport, a universal student allowance and a 20 per cent pay rise.

Leader James Shaw and candidate Chloe Swarbrick announced the party's "student support plan" at Otago University in Dunedin today.

Mr Shaw says they will make all post-graduate students eligible for a student allowance, as "a first step towards eventually making all students eligible".

The policy would initially cost $300 million dollars a year.

Mr Shaw says students are the only group in society expected to borrow just to get by.

"We believe that students should be supported so that they can focus on learning the skills they need to contribute to a smart, innovative economy and fairer society," he says.

The Greens also want to increase student allowances by 20 per cent, so that a student under 24-years-old not living with their parents would receive $39.30 more each week, while a single parent who is studying will be $130 better off.

A so-called "Green Card" would give all tertiary students and apprentices free public transport in off-peak hours, while the party would restore access to student loans and allowances beyond seven years.

"National's caps on student allowances have forced students into greater debt and are a barrier for students from lower income families to keep studying.

"Rising costs of living and higher rents are making life increasingly hard for students, and the Green Party has a plan to fix that," Mr Shaw says.