Nicola Sturgeon was accused of hiding her support for fracking as Scottish Labour vowed to ban the controversial technique in Scotland.
The SNP issued a moratorium in January last year on granting applications for unconventional oil and gas extraction.
Scottish Labour leader Kezia Dugdale revealed a hardening of her party’s stance on fracking at First Minister’s Questions.
She challenged the SNP leader to follow other parties in revealing where her party stands.
“Scottish Labour will go into the election with a very clear manifesto commitment,” Ms Dugdale said.
“We will oppose fracking. If Jim Ratcliffe of Ineos [pro-fracking industrialist] can get a straight answer why can’t the people of Scotland?”
She later added: “Her maybes aye, maybes naw response can mean only one thing Nicola Sturgeon plans to give the green light if she is re-elected in May.”
Ms Sturgeon said they are clear on fracking by imposing the temporary ban until all the scientific evidence is gathered.
“We will not allow fracking in Scotland because we will not take risks with our environment where there are still unanswered questions. That’s why we have got a moratorium in place,” she said.
Last week Liberal Democrat members voted to back fracking in the wake of a report that found it was safe if properly regulated.
The Tories support the energy extraction technique, while the Greens are strongly opposed. Climate change scientists have said the UK must move away from fossil fuels as energy sources.
Also at FMQs, Ms Sturgeon clashed with Scottish Conservatives leader Ruth Davidson over the future of jobs at Trident’s Faslane base and the First Minister was made to defend the council tax reforms unveiled yesterday.
She also expressed her support for a BBC Scottish Six news programme.