University graduates earning as little as $45,000 a year will have to start repaying their student loans after the government secured crossbench support for plans to recoup $245 million in tertiary debt.

Under a cost-saving bill, the threshold over which graduates will have to repay at least 1 per cent of their debt each year will drop from $56,000 to just $45,000 a year.

From July 1, graduates earning $45,000 will have to forfeit $450 a year in debt repayments, when before they paid nothing. And for graduates earning $55,000 – roughly the median wage in Australia – their yearly repayments will be $1375.

All students will also be barred from receiving more than $104,440 in taxpayer-backed loans until they have repaid existing debts.

The changes will take effect from July 1 after the government on Tuesday received the Centre Alliance’s backing for a revised bill in the Senate, adding to votes from One Nation, Liberal Democrat David Leyonhjelm and Independent Tim Storer.

The government had originally proposed a lower threshold of $42,000 and a lifetime cap on loans. The government has estimated the revised reform package will boost government coffers by $245.2 million over four years.

National Union of Students education officer Con Karavias told The New Daily he was “extremely outraged” over the changes, warning they would deter poorer students from going to university.

“Education is already hard to afford for students in Australia,” he said.

“These measures are going to keep already poor students in poverty for longer.”

Education Minister Simon Birmingham previously said the move was a necessary response to students “racking up unnecessary loans”.

Labor and the Greens both opposed the bill, with Greens leader Richard Di Natale saying young people were being “royally screwed over” by the Coalition.

“If you’re a young person and you’re taking home 700 bucks a week, let’s face it, it’s not a goldmine,” Di Natale said in Parliament on Tuesday.

“Once you’ve ended up paying for your rent, your energy bills, your grocery, your shopping needs, your transport needs, there’s very little left to spend on anything else.”

Under Tony Abbott, the Coalition made an unsuccessful attempt to deregulate fees and slash subsidies by about a fifth. A bid by the Turnbull government last year to cut university funding also failed.