Nicola Sturgeon is to promote a message of “hope and optimism” in her speech to the SNP conference in Glasgow.
The party leader and first minister will close the three-day event by hitting out at “unfolding calamity” and “despair” at Westminster.
She will contrast this by painting an independent Scotland as “a beacon of progressive values”.
Ms Sturgeon will also set out a “fair work first” approach to business support grants and contracts.
The SNP leader kicked off the conference by announcing that the party’s 35 MPs at Westminster would vote in favour of a new referendum on Brexit, were such a question to be tabled at Parliament.
This was endorsed by members via a topical resolution, with the party also promoting its policy of the UK remaining in the EU’s single market and customs union.
Ms Sturgeon will return to the constitutional theme in her speech, saying that an independent Scotland could offer “equality, opportunity, diversity and fairness”.
She will say: “The Westminster government stumbles from day to day and disaster to disaster. It’s hard to watch that unfolding calamity and feel anything other than despair.
“So it is up to us – now more than ever – to offer optimism and hope.
“Just think how much more hope will be possible when we take Scotland’s future into Scotland’s hands and become an independent country.”
The UK government has placed itself in opposition to a second referendum either on independence or on Brexit.
The prime minister’s official spokeswoman said Scotland “had an independence referendum four years ago and vote decisively to remain in the UK”, adding that “now is not the time” for a fresh vote.
The other main speakers on the final day of the conference are Finance Secretary Derek Mackay – who will make an announcement on infrastructure and issue a Budget challenge to Chancellor Philip Hammond – and Constitutional Relations Secretary Mike Russell.
On Monday, the party’s Westminster leader Ian Blackford told delegates that the “democratic outrage” of Brexit was “crystallising” the case for independence.
But at a fringe event, Mr Russell warned members against rushing into a “heroic defeat” in a second independence referendum, saying the party must move “intelligently, rationally, thoughtfully, step by step, and not set ourselves artificial timescales”.
After one delegate said members were “very frustrated with constantly being told to just wait”, Mr Russell said: “The why of independence is more important than the when of independence the moment, because the when is not in our gift.”
Meanwhile Education Secretary John Swinney used his speech to defend “controversial” education reforms which have seen the government defeated by the opposition at Holyrood.
Mr Swinney is set to update MSPs after the October recess on the future of standardised assessments for P1 pupils, after parliament voted to say they should be “halted”.
He said he was “looking at ways to reassure” people who had “genuine” concerns about the policy.
But he said opposition parties had been motivated by “political opportunism”, calling it “the worst example of the tribal, SNP-bad politics of the unionist parties I have seen in years”.
This has been sharply criticised by those parties, with the Conservatives saying the SNP “simply does not want to listen to any vote with which they disagree”.