Schools are shunning lessons on the Tiananmen Square massacre in the run-up to the handover.
And there are fears the materials, which include pictures of the massacre and of tanks, will not survive beyond next year.
The number of primary and secondary schools buying or borrowing the audio-visual teaching materials from the Professional Teachers Union has been dropping.
More than 890 schools or individuals asked for the kits in the year following the 1989 killings. Last year, the number was only 37.
This year, 43 applied to the union for the packs, which include 140 pictures of activities of the democratic movement in China, from April to June, 1989, and a video of 10 songs recorded at a Happy Valley concert for democracy.
But items, including a video of a speech by student dissident Chai Ling and pictures by American journalist Larry Hanbrook taken in Tiananmen Square, have received little interest.
Tsui Hon-kwong, head of the union's resource centre, said the 24 teaching kits - costing from $2 to $30, plus a deposit of between $10 and $1,200 - were useful for students learning modern Chinese history.
