The Scottish Executive said it still had to formally agree its position
on genetically modified crops.
The executive still has to decide its policy on GM maize
The executive played down reports it was set to reject plans to grow GM maize by urging farmers to voluntarily
declare themselves GM free zones.
A spokesman said it would make an official announcement in due course and not rely on any voluntary schemes.
The Greens dismissed the executive's words and claimed it had no plans to prevent GM crops being grown.
Environment Secretary Margaret Beckett is expected to give the go-ahead to growing the controversial technology in the UK this week.
But on Friday, the influential cross-party committee of Westminster MPs, the environmental audit committee, said there was no valid scientific basis for the commercialisation of GM maize.
The Scottish Green Party said this should be enough
to persuade the executive not to plant the crops.
But an executive spokesman said: "The Scottish Executive has still to formally agree its position on GM.
"We have been clear any decisions must take full account of all the evidence available to us, including the public's response to the GM dialogue.
"We recognise the level of concern that has been expressed and will inform any decision taken by Scottish ministers.
"An announcement will be made in due course."
Green MSP Mark Ruskell said reports of the voluntary scheme made it appear that the executive was against GM agriculture but the reality was that it was not.
He claimed Scottish ministers were afraid to use their veto to prevent GM maize being put on the approved UK seed list.
Mr Ruskell said: "It may sound like the executive is doing something, indeed it is welcome to hear ministers suggest they are against GM, but the real story here is they have fallen short of the action needed to stop it.
"Environment Minister Allan Wilson and Jack McConnell still have the power to prevent GM Maize getting onto the UK seed list, yet they have decided to cave in to Beckett.
"The executive is engaged in thinly veiled spin aimed at covering up the lack of meaningful action.
"This is a cave-in, make no mistake."
Just say no
The Scottish National Party echoed the call for the executive to prevent GM crops being grown
Deputy leader Roseanna Cunningham said: "The Scottish Executive must say no to GM crops in Scotland.
"Instead of waiting for Margaret Beckett to make a decision for the whole of the UK, the executive must make up its own mind.
"The Scottish Executive minister must make a decision based on what the people of Scotland want and that is no GM crops north of the border."