The Opposition NDP wants an independent review conducted of a government plan to use a public-private partnership to build nine new schools in Saskatchewan.

NDP education critic Trent Wotherspoon said Monday there are no hard numbers to back up the government's claim that building the schools in such manner would be less expensive than other, more traditional, approaches.

Wotherspoon said there needs to be more information on the full cost to taxpayers.

The new schools, announced a week ago by Premier Brad Wall, would be joint-use -- meaning public on one side and Catholic on the other with shared spaces such as gymnasiums or daycares in the middle.

Wall said traditional construction costs would be about $450 million, but the P3 approach could save $30 million.

On Monday Infrastructure Minister Don McMorris said it is tough to pinpoint exactly how much money will be saved, but the estimate was based on a similar approach to building schools in Alberta.

The opposition says Saskatchewan people deserve an independent assessment of which is the best way to pay for new schools.

"[The] government's taking sort of a 'Just trust us' approach," Wotherspoon said Monday. "What Saskatchewan people deserve is the hard numbers, the real numbers. And they also need to articulate the entire full life-cycle cost to Saskatchewan people."

Wotherspoon said he will lay out details for how the deal can be independently assessed before the end of the week.

McMorris said the government plans to keep a close watch on the P3 process.

"We're going to look at that as we move forward," McMorris said. "We've made the announcement, we're going to move forward. If this isn't going to save the taxpayers money in the long run, we're not going to move forward with it."

(With files from CBC's Stefani Langenegger and The Canadian Press)