David Cameron may "play fast and loose" with membership of the European Union but the SNP will "campaign positively" to keep Scotland and the UK in Europe, Nicola Sturgeon will pledge.
The Scottish First Minister will accuse Mr Cameron of "pandering to eurosceptics" in the Conservative Party as she attacks his "failure of leadership" on the issue.
The SNP leader will use the speech at the end of her party's conference in Aberdeen to make clear that she wants Britain to remain part of the European community.
Ms Sturgeon will say: "David Cameron might play fast and loose with our place in Europe. Be in no doubt - the SNP will campaign positively for Scotland, and the UK, to stay in the European Union."
The UK Government has pledged to hold an in/out referendum on Britain's membership of the EU before the end of 2017.
But Ms Sturgeon will speak of her "despair at the failure of leadership of a Prime Minister pandering to eurosceptics in his party but unable to articulate clearly and precisely what it is he is seeking to renegotiate".
The First Minister will also use her address to make the case against UK military intervention in Syria, arguing: "What is needed is not more bombing but a renewed and intensive diplomatic initiative led by the UN."
UK motivation to use the armed forces "appears to be based on a need to do something rather than any real consideration of whether the action proposed will make a positive difference", she will say.
But the risk is action such as air strikes "will simply add to the already unimaginable human suffering".
With millions of people having fled Syria the SNP leader will also argue the "prospect of UK withdrawal from the EU seems even more misguided" as she again calls on the UK Government to "do more as part of a co-ordinated European response" to help refugees who have travelled to Europe.
The First Minister's speech comes at the end of the SNP's biggest ever conference, with the party's membership now totalling almost 115,000.
Scottish nationalists won all but three of the 59 constituencies north of the border in May's general election, and Ms Sturgeon is aiming for her party to win a historic third term in office in next year's Holyrood vote.
That election campaign will be her first as First Minister, prompting Ms Sturgeon to ask voters to put their trust in her.
"Over these next few months, as we prepare to seek re-election, I won't pretend that we are perfect. Or that I am perfect," she will say.
"But I will promise this. We will always strive to be the best we can be. And we will serve this country with imagination, courage, humility and always to the very best of our abilities."
The SNP's manifesto for next May's Scottish Parliament elections will "rise to the challenges of the future", she will add.
Ms Sturgeon will also pledge £200 million of investment to expand specialist centres for planned operations in the NHS in Scotland if her party is re-elected.
The Golden Jubilee Hospital in Clydebank has been a "huge success", with staff there carrying out hip and knee replacements and cataract operations and "helping to take pressure off our emergency hospitals".
The First Minister will announce: "We now intend to extend that model. Over the next parliament we will invest £200 million to create a new network of elective treatment centres.
"We will extend the Golden Jubilee and develop new centres at St John's in Livingston, at Edinburgh Royal Infirmary, at Ninewells in Dundee, at Raigmore in Inverness and here in this city at Aberdeen Royal Infirmary."