Students would get free tertiary study but only by working in New Zealand for a time equivalent to their length of study, under New Zealand First policy.
The announcement of the policy detail means NZ First, Labour and the Green Party are all committed to some version of free tertiary education.
Under the NZ First "up front investment" policy, each student would have their "skill debt" monitored by Inland Revenue.
Each year in New Zealand would reduce skill debt by a year. For example, a Bachelor of Arts student would need to work here for three years to wipe their skill debt.
NZ First education spokeswoman Tracey Martin released details of the policy at the party's annual conference in Dunedin.
"Trade offs would be made for those students that needed to go and get international experience, their professional body would be required to match them with another person who needs international experience from say the UK or whatever."
For those with existing student debt, under the policy the Government would match each dollar repaid if the graduate was working in New Zealand.
The IRD would still chase up students for overdue repayments, but would stop the worst offenders as they entered New Zealand, and not arrest them as they leave the country, as has happened in two cases recently.
The current cost of the tertiary system was $4.183 billion, or equivalent to 1.67 per cent of GDP, Martin said, and her policy would cost $4.638 billion, or 1.86 per cent of GDP.
The policy would also introduce a universal living allowance, regardless of how much a student's parents earn.
Martin said the bonding policy would not kill off the Kiwi OE.
"If you are maybe 25 by the time you have paid off your whole debt, you are not exactly old...and it is possible we could negotiate the one-year repayment holiday to be there."
Tertiary Education, Skills and Employment Minister Steven Joyce said the proposal was "completely unsustainable" and would cost the country billions of dollars.
"We already effectively incentivise people not going overseas by having interest-free loans if they remain in New Zealand, and 85 per cent of student loan borrowers with the IRD are currently in New Zealand."
The average pay-off time for a student loan was just under six years, Joyce said.
"It is just a multi-billion dollar promise that NZ First are making that they probably never expect to have to follow through with."
In January, Labour leader Andrew Little announced in a State of the Nation speech in Auckland Labour would provide three years of post-school study for every person in the country without a previous tertiary qualification.
Currently around 180,000 people attend university.
The Green Party wants to gradually move to free tertiary education, and investigate bonding or other mechanisms of contribution in exchange for free study.
MEDICAL MARIJUANA SHOULD BE INVESTIGATED - NZ FIRST DELEGATES
NZ First delegates have voted on a number of policy remits put forward by different branches. If accepted, they will be examined by caucus.
A remit that was carried with strong support was put forward by the Whanganui branch and called for NZ First to demand a full government investigation into the use of "low THC medical marijuana" for the treatment of some illnesses.
Delegates also voted to carry another remit for NZ First to support a steady phasing out of battery hen farming, and to require all people with a history of serious domestic violence and subject to a protection order to wear a GPS bracelet.