An action group has been set up to find new ways of recruiting Gaelic-medium teachers - particularly for the secondary sector.
More distance learning, part-time teacher training courses and intensive language courses will be considered as potential routes to enticing more teachers.
Speaking on Wednesday, when the first stage of the Gaelic Language Bill was debated, Mr Peacock said: "We need to do more to ensure that Gaelic-medium education does not become a victim of its own success. We now have pupils who have spent their entire primary career in Gaelic-medium units, but when they reach secondary school the opportunities available to them can be patchy.
"Glasgow's new Gaelic-medium secondary school, coupled with the virtual secondary network currently being established, will go a long way to address the problem. But these solutions also create even greater demand."
Mr Peacock added: "There are many fluent Gaelic speakers who might not have considered a teaching career - perhaps because they can't study full-time or don't live near a teacher training college. That is why we need to introduce more flexible approaches. There is also a vast pool of existing teachers, working in Scottish schools, who could teach in Gaelic but choose not to."
The group, which will be chaired by Matthew MacIver, chief executive of the General Teaching Council for Scotland, has been asked to report before the summer.