Michael Foxley, vice-convener of Highland Council, said that a minimum of three Gaelic teachers per high school was essential if the language was to develop across at least five subjects - enough to provide a core curriculum.
"Unless we get these people into secondary schools, everyone ends up at primary 7 Gaelic. This is still not being taken seriously," Dr Foxley said.
He accused the Scottish Executive of stalling on funds for Gaelic secondary teaching for two years and failing to push through political commitments. "They activated the Lews Castle courses (in Stornoway) but did not give them the funding. Lews Castle courses are not running until next year but were announced two years ago," Dr Foxley said.
He also criticised careers services for failing to promote rewarding jobs in Gaelic.
Bruce Robertson, Highland's education director, said it was "sad, disappointing and embarrassing" to have around 1,000 Highland pupils currently learning through Gaelic-medium education (GME) who had so few opportunities to take secondary subjects.
He appealed for different routes into teaching, such as Highland's new distance learning course run with Aberdeen University.
"We have come to a point where the pool of prospective teachers that are willing to go to Glasgow or Aberdeen or wherever to train is beginning to dry up. We need to be encouraging more innovative approaches to teacher training in the Highlands and islands," Mr Robertson said.
Duncan Ferguson, chair of the new Gaelic Board (Bord na Gaidhlig) set up by the Executive to promote the language, accepted the need for alternative ways into teaching. "I do see it as a priority if we are to make progress," Mr Ferguson, headteacher of Plockton High in Wester Ross, said.
Peter Peacock, Education Minister, told a pre-conference dinner: "We are beginning to see teacher training numbers improve but we have got much more to do."
Figures released by the Executive show 1,925 primary pupils learning through GME and 375 in secondary. Only 19 secondaries offer Gaelic-medium teaching.
In the primary sector, 25 student teachers are expected to graduate this summer but Dr Foxley believes this is at least 10 short of the number required.
Despite the concerns, Mr Peacock said that in the 21 years since he had entered politics in Highland, Gaelic-medium learning had "moved forward phenomenally" and gave assurances it would be taken further once the language had secure legal status after the imminent Gaelic language Bill.
"Beyond the Bill, there are huge opportunities in education. It is fundamental to what you can do in the future," Mr Peacock said.
Leader, page 24