Retiring West Australian Liberal Senator Chris Back has threatened to vote against the Quality Schools funding package.

Senator Back said he was concerned that the plan to move all schools to a simpler funding model would disadvantage Catholic institutions.

The government passed the reforms, nicknamed ‘Gonksi 2.0’ after a proposal under former prime minister Julia Gillard, on Friday.

At Stawell’s St Patrick’s Primary School, director of Catholic education Audrey Brown joined other schools last month in using their newsletter to urge the community to oppose the funding model.

“We welcome and offer support to all families who desire an education in which we ‘strive for the greater gifts’. That is not something that we want to lose,” she wrote. 

Ararat St Mary’s Primary School principal Tom Hogan said he hoped negotiations with independent senators would deliver a better deal.

“We don’t want to see kids disadvantaged for attending a Catholic school,” he said.

“The proposals are not considering the needs of children in Catholic schools and would have an impact on funding. We don’t want to charge extensive fees for children to attend our school.”

Mr Hogan said the biggest impact would be in the long term.

A special government website set up to explain the reforms has stated St Mary’s, along with most Catholic schools in western Victoria, would be better off.

Mr Hogan said he had been given different figures.

Member for Wannon Dan Tehan and Member for Mallee Andrew Broad voted for the reforms in the lower house last month.