Ronnie Smith, the institute's general secretary, cautioned any incoming Westminster administration that the McCrone agreement would only work if long-term funding was assured for local authorities and schools under the Scottish Parliament's block settlement.
Schools would need 4,000 more teachers while the plans for professional development at the heart of the agreement "would not come cheap".
Mr Smith said: "Teachers and local authorities must be supported to ensure that all continuing professional develpment is of quality and that teachers can access it without financial disadvantage to themselves."
Any follow-up to Jack McConnell's task force on pupil indiscipline would also bring additional costs. No initiative would work effectively without a fresh injection of cash.
Mr Smith said: "Many of Scotland's schools are in a shabby state or worse. Recent governments have relied over much on the private sector to provide the funding to build new schools. But without a significant input from government there is no prospect of high quality, newly built or newly refurbished schools which meet the needs of communities and young people."
He urged teachers to make their vote count as Westminster still had a real say over young people's futures.