Lib Dems push for income tax cuts in future coalition talks
Raising the personal income tax allowance to £12,500 will be a key Lib Dem demand in any coalition talks after the 2015 election, the party has said.
Treasury Chief Secretary Danny Alexander said raising the threshold for the amount people can earn before paying income tax was a "top priority".
He said the economic recovery would not have happened without the Lib Dems.
Meeting for their spring conference, Lib Dems also backed extending the time before EU migrants can claim benefits.
The new policy would mean EU migrants to the UK could claim benefits only after six months.
The plan would also make it easier for foreign students to stay and work in the UK and for immigrants to bring their families to live with them.
'Our own values'
Mr Alexander told the conference that another rise of at least £500 in the personal income tax allowance - amounting to a tax cut of £100 a year - would be earmarked for the first Budget or Autumn Statement after the election.
Party leader Nick Clegg has already called for a further £500 increase to be included in this month's Budget.
The income tax allowance stood at £6,475 when the coalition government was formed in May 2010. Since 2010, it has risen to £10,000.
Mr Alexander confirmed that increasing the threshold again would be written into the party's manifesto for the 2015 general election.
"We will fight the next election with our own ideas, our own policies, our own values - no-one else's," he said during his conference speech on Saturday.
"And I can tell you that a top priority in any negotiation will be our aspiration to raise the personal allowance dramatically again in the next Parliament."
He also renewed his party's criticism of its coalition partners, the Conservatives.
"In 2010 the Conservatives wanted inheritance tax cuts for millionaires; we fought for and delivered tax cuts for working people," Mr Alexander said.
"In 2011 the Conservatives wanted 'shares for rights'; we fought for and delivered tax cuts for working people.
"In 2013 the Conservatives wanted a tax break for married couples that excluded millions of families; we fought for and delivered - you guessed it - more tax cuts for working people.
"Now, belatedly, some Tories are lamely trying to claim credit.
"Don't get me wrong, it must be hard to be a Tory in a Treasury delivering so much Lib Dem policy, so it's no surprise if some of them have gone native."
Mr Alexander said the "right conditions for this [economic] recovery would not have happened without the Liberal Democrats in government".
"Every job that's been created, every apprenticeship opened up, every tax cut delivered for working people has our Liberal Democrat DNA running through it," he said.
In a further reference to the Conservatives, Mr Alexander said the government could not rely on "cutting public spending and targeting welfare to finish the job" of improving the economy.
Later, he told the BBC how the next government "has to be a coalition" if the 2015 general election results in a hung parliament.
The Prime Minister, David Cameron, is reportedly considering fighting the next election on a promise not to form a new coalition government even if his party falls short of a majority.
However, Mr Alexander said: "It has to be a coalition because I think that in a hung parliament you need to have a government that's strong and stable and able to take decisions.
"That's what this country has benefited from over the past four years."
Mr Alexander said the Lib Dems would look to see which party had the strongest mandate in the event of a hung parliament.
The treasury chief secretary is due to lead his party's negotiating team in any talks after the election about forming a new coalition.
Asked about the Lib Dems' tax proposals, Labour's shadow chief secretary, Chris Leslie, said they should "come clean" about how they would pay for it.
"Will they just hit families and pensioners by raising VAT again?" he said.
Elsewhere at the spring conference, Business Secretary Vince Cable backed Lib Dem calls to make it easier for foreign students to stay and work in the UK and for immigrants to bring their families to live with them.
Mr Cable said his party had an "acute responsibility" to address issues surrounding immigration.
During a debate on immigration policy, he said: "It was never more necessary to have a party that was willing to stand up on this toxic issue and address it from the point of view of realism and evidence and fact."
His comments come days after Conservative Immigration Minister James Brokenshire spoke out against Mr Cable's comments that rising immigration was "good news" for the country.