The Scottish Secondary Teachers' Association (SSTA) said the move – announced last year – was unnecessary because most English teachers already taught Scottish texts.
And the Educational Institute of Scotland (EIS), which first attacked the plans last year, said teachers had not been consulted properly on the issue.
The EIS is concerned the Scottish Government is using a compulsory question to dictate what is taught in schools, rather than relying on the interests of pupils or teachers' skills.
Alan McKenzie, the SSTA's acting general secretary, said: "It seems surprising that such exhortation is necessary since the English curriculum in most schools includes a significant number of Scottish texts. It would be interesting to identify just what the true extent of the problem is."
An EIS spokesman added: "We share a desire to see more Scottish literature studied in our schools, but we are opposed to plans to introduce a compulsory Scottish text question.
"Regrettably, neither the EIS nor English teachers generally were consulted on this matter"
The compulsory question was announced last year by the Scottish Government after a recommendation by the Scottish Studies Working Group.
The working group, whose members included Makar Liz Lochhead, university professors, teachers and officials from Education Scotland, Historic Scotland, Creative Scotland and the Scottish Qualifications Authority (SQA), was set up after concerns the teaching of Scottish literature was an afterthought in some schools.