Nick Clegg will insist he is working flat-out to make coalition policies "fairer" as he bids to soothe fractious Liberal Democrat activists.
The Deputy Prime Minister will launch his party's annual conference with a promise to push for more taxes on unearned wealth.
The gathering in Brighton could prove a difficult one for Mr Clegg, following the collapse of his Lords reform plans and consistently dire poll ratings. Amid renewed speculation over his future as leader, he again sought to draw a line under the damaging tuition fees U-turn earlier this week by issuing a grovelling apology.
However, there is still festering resentment among the party's rank-and-file on the issue. Mr Clegg is also facing pressure to ensure the Government does not back away from key environmental policies, and there will be calls for the Government to ease up on austerity to help the economy.
Speaking at a rally to open the conference on Saturday evening, Mr Clegg will say he still believes it was right to go into coalition with the Tories.
"We chose to govern with our political opponents because our country needed a stable government at a critical time," he is to say.
"Not because it was easy but because it was right. That is still true. We have avoided an economic catastrophe. We have steadied the ship. Now we must set it sailing. And as we do so Liberal Democrats will not stop fighting to make this Government and this country fairer."
Hinting that he will step up efforts to bring in so-called wealth taxes - such as the levy on mansions favoured by many activists - Mr Clegg will add: "One of the most important ways we can do that is by making taxes fairer.
"It's just wrong that people on low and middle incomes who work hard and play by the rules are taxed so much while Russian oligarchs pay the same council tax as some people do on a family home.
"Liberal Democrats are fighting to change that. Lower taxes on work and more on unearned wealth. I want to reward people who put in a proper shift, not those who sit on a fortune. People for whom a bonus means a few extra quid at Christmas not a million pound windfall."