Sir Menzies Campbell is facing his first test as the new Lib Dem leader after urging party activists to back the part-privatisation of Royal Mail.
Sir Menzies said the party needs new ideas
The controversial plan was last year rejected by delegates at the party's autumn conference in Blackpool.
But Sir Menzies, who is in Harrogate for the party's spring conference, urged them to think again when they vote on the issue later.
He has told activists he is "ambitious for Britain" and for the Lib Dems.
Sir Menzies said: "Keeping 51% of Royal Mail in the hands of the government and of employees is in line with our long-held Liberal beliefs in employee share ownership.
"I believe this motion captures our ability to tackle difficult issues head-on, developing innovative liberal solutions to challenges, which the other two parties refuse to face."
The party is expected to claim selling off 49% of Royal Mail will raise £2bn to modernise post office branches.
Sir Menzies was confirmed as Liberal Democrat leader on Thursday, beating economics spokesman Chris Huhne and party president Simon Hughes in a ballot of all-party members.
The 64-year-old says he is ready to take risks to modernise the party.
At a victory rally at the Harrogate conference hotel, at which there was standing room only, he told activists he was "ambitious for Britain" and for the Liberal Democrats.
He hailed the party's MPs as the "best and the brightest of the new generation of British politics".
But he also warned the party it needed new ideas.
"Our party has always been the most intellectually innovative in British politics. We need fresh ideas and new thinking."
He used his speech to announce a trust fund which would aim to provide the resources to encourage more women and ethnic minorities to stand as election candidates.
Sir Menzies is expected to carry out a reshuffle of the party's front bench team on Monday, but he has said he will not offer his predecessor Charles Kennedy a job.
In forming a front bench team, Sir Menzies is likely to consider what role defeated leadership rivals Mr Hughes and Mr Huhne should play and whether or not to reward those who supported his campaign.
Backers included Ed Davey, Sarah Teather, Vincent Cable, Nick Clegg and David Laws.
The post of deputy leader - which Sir Menzies himself held as well as being foreign affairs spokesman - has yet to be decided upon.
He is due to make his first major speech as leader on Sunday.
The leadership election was called after Mr Kennedy stepped down earlier this year days after revealing he had sought help for a drink problem.