States members were made aware of the financial implications of committing millions of pounds to education this week, says Guernsey's finance chief. Building work on new schools at Les Nicolles will begin this summer after members approved the first phase.
But some States politicians said they did not have enough information to make the decision.
Treasury and Resources Minister Lyndon Trott, said: "Members were fully aware of the impacts."
Guernsey's teachers have welcomed the States' decision to go ahead with a �50m secondary school complex.
However they also have concerns about having enough money left over to cover the cost of raising the school leaving age in 2008.