The internet is helping a small number of pupils to pass off "ready-cooked" exam coursework as their own, according to a teachers' union.
Handheld computers could help exam cheats
The Scottish Secondary Teachers' Association warned that the problem could get worse through the use of mobile phones and handheld organisers.
It called for new standards to be put in place for verifying exam coursework.
The union also wants research into computer systems, used by some US schools, that aim to detect plagiarism.
SSTA general secretary David Eaglesham said the problem had become increasingly evident over the years.
"A wide range of courses at National Qualification and Standard Grade require the submission of course work as part of the examination," he said.
"It is becoming an increasingly difficult problem to separate legitimate use of external sources and plagiarism in the work of candidates.
"We must act now to tackle what will only become an ever-greater problem due to miniaturisation of technology."
He said the Curriculum for Excellence would require some re-design of examinations and that this would provide an ideal opportunity for the Scottish Executive and the Scottish Qualifications Authority to tackle the issue of cheats.
"We must be able to reassure pupils, parents and the wider community that examinations remain a scrupulous, fair and accurate illustration of the true ability of a pupil," he said.