But Labor also insists it won't let the government cut $2.3 billion from universities funding, even though Labor itself proposed the cuts in April to pay for its new schools funding system.
Programme for International Student Assessment (PISA) results show Australian school results in maths and reading continued to slip in international comparisons - and when compared with the performance of Australian students over the past decade.
The results also show increasing gaps between advantaged students and those from poor or indigenous backgrounds or remote areas.
"Our children are being let down by a long-time broken education system," Opposition Leader Bill Shorten told reporters in Canberra.
"It's time to get on board and make sure that we have an education system which is not betraying the future capacities of our young children."
Education Minister Christopher Pyne says the PISA results show the extra money the former Labor government put into schools over the past five years didn't lift student performance.
Mr Shorten didn't believe it could be deduced from the findings that more funding was the answer, adding it took a long time to implement wide-ranging reform.
"The real issues were not just the funding ... it's what the funding is used for," he said.
Prime Minister Tony Abbott has committed to match Labor's needs-based Gonski schools funding for the next four years to the tune of $2.8 billion.
Labor had planned to spend a total $11 billion of federal money on schools over six years from 2014.
It's unclear whether all states still have to abide by conditions set by Labor under the Gonski plan, including pledges for co-commitments and improvements to teacher quality and student outcomes.
The opposition says it can't see any point in letting the government cut money from universities if it won't commit to the full schools plan.
"They want all the cuts but they're not committing to the spend," education spokeswoman Kate Ellis said.
