The Scottish Government has launched a drive to recruit new scientific advisers after being unable to fill a top role.

The position of Scotland's chief scientific adviser (CSA) has been vacant since December when Professor Muffy Calder stood down from the job.

Last month she spoke out against the Government's controversial decision to ban genetically modified crops, saying it did not appear to be based on scientific evidence and could have ''apocalyptic'' consequences.

No-one has been appointed to replace her despite a recruitment process in the spring.

The role is currently being covered by the remaining chief scientists for health and rural affairs, food and the environment, and will re-advertised by the end of January.

The Government said it would first review the post to ensure "maximum value" and attract a broad field of candidates.

Applications are also being sought for membership of the Scottish Science Advisory Council (SSAC) from next month.

Education Secretary Angela Constance said: "I am writing to all university principals and the presidents of our learned societies to encourage them to work with us to ensure we recruit a new chief scientific adviser that will deliver for Scotland.

"This critical role will reflect our commitment to drawing on the very best scientific advice and expertise.

"We will also soon advertise for new members of our highest level group of independent science advisers - the SSAC.

"It has the potential to add real value in all policy areas connected to science and the SSAC will also keep ministers informed about new technologies and other scientific developments."

Ms Constance praised science centres and festivals for their record in gender balance but said more action was needed to get women into all levels of science.

She added: "Having women in senior, visible roles help to show girls and young women that choosing science can open up a range of career possibilities.

"That is why it is so important to appeal to a wide range of experts as scientific advisers to government."

Labour's opportunity spokesman Iain Gray welcomed the announcement but added:"It is worrying that there has been no chief scientific adviser and no meeting of the Scottish Scientific Advisory Council for the past nine months.

"That apparent lack of interest in science and scientific advice is just unacceptable in the government of a modern 21st-century country, especially one with Scotland's scientific pedigree.

"To meet some of the big education, environmental and economic challenges Scotland faces we need the best scientific minds available. The SNP must not turn their back on science in Scotland."