CANBERRA, June 5 - More than 400 independent schools will receive lower funding growth than under existing legislation, and two dozen schools will have their funding cut, but representatives say the new model is consistent and will allow for planning.

"We didn't want to argue for anyone to lose money - we've never said that publicly - but if the government has decided this is the best way to introduce a fair model of funding, then we've accepted that," Geoff Newcombe, from the Association of Independent Schools of NSW, told a Senate inquiry on Monday.

However, Catholic school authorities will warn senators about rushing to pass the new funding plan, which they say will lock in disadvantage for public and low-fee private schools.

A Senate committee examining legislation for the new funding plan, dubbed Gonski 2.0, is hearing from Catholic and independent school representatives, principals and federal education department officials at its second public session.

The Catholic sector has been a savage critic of the plan, warning of major fee hikes and possible school closures if it passes.

But the government argues the sector will get an extra $1.2 billion over the next four years and more across the decade and there should be no need for such a dramatic reaction.

The National Catholic Education Commission says the government seems to be trying to rush through a 10-year plan that risked disadvantaging public schools and low-fee Catholic and independent schools.

"The minister might not see that - or might be choosing not to see it," acting executive director Danielle Cronin said.

"(Senators) won't want to see the creation of a two-tiered school system, in which parents choose a 'free' public education or a high-fee non-government school, because the minister's model risks eliminating the affordable option for Australian families."

Cronin also said the legislation before parliament would lock in "an inadequate measure of parental capacity to pay fees".

Individual Catholic dioceses in Brisbane and Newcastle-Maitland have apparently broken away from the national body's position, writing to parents to reassure them fees will not have to dramatically increase in 2018.

The government needs 10 extra Senate votes to pass the legislation, with Labor opposed to the plan it says cuts $22 billion from schools over the decade.

The Greens and Nick Xenophon's team of three senators appear to be favouring the government's plan with some changes, to ensure money gets to the neediest schools faster.