Ed Miliband urges 'responsible' opposition to cuts
Opposition to proposed spending cuts must be "responsible", Labour leadership candidate Ed Miliband said.
At a leadership hustings at the TUC Congress Mr Miliband said he did not support calls by some union figures for a campaign of civil disobedience.
Rival candidate David Miliband, seen as the front-runner in the contest, said Labour needed to win the political argument against the budget squeeze.
Ed Balls, Andy Burnham and Diane Abbott also took part in the event.
It was the last hustings of the four-month, five-way campaign, with the outcome of the leadership election being announced at the party's conference later this month.
Making their pitches to union delegates - a key constituent in the voting process - Shadow Foreign Secretary David Miliband said he could unite the party, "reach out" to the public and be a "credible" prime minister.
His brother Ed, who has argued he has the momentum in the contest in its final stages, said he was not the candidate of the "New Labour establishment" but could lead the "profound change" the party needed to win back power.
Some Labour sources have suggested the contest is too close to call and could hinge on how the second preference votes for each of the candidates are distributed.
The BBC's Political Editor Nick Robinson said all the candidates were well received and the Milibands had each sought to emphasise their own different strengths as the race goes down to the wire.
Each of the candidates was asked how budget cuts of between 25% and 40% set to be announced in next month's spending review could best be fought.
Earlier on Monday, union delegates backed joint industrial action if "attacks" on jobs, pensions and public services went ahead.
Calling for a "responsible approach", Ed Miliband said the campaign against cuts needed to have the support of both public sector workers and users of public services.
Mr Miliband, who has argued he has the momentum in the contest, said those leading opposition to the cuts had a "heavy responsibility" to build the broadest coalition of support against them.
He rejected suggestions by union leader Bob Crow that acts of civil disobedience - such as protesters scaling Parliament or 10 Downing Street - would be justified to get workers' message across.
"I am not in favour of civil disobedience," he said. "I am in favour of lawful action."
David Miliband said he would lead the "most fearless and imaginative" campaign against the cuts, stressing "let's not get angry, let's get organised".
However, he would not be drawn specifically on whether he would join a proposed demonstration planned for 19 October - the day before the spending review.
Shadow Education Secretary Ed Balls said Labour could not afford to lose the key economic argument of the time - over how quickly to reduce the deficit - as the party had done in 1983 and 1992.
Calling for £6bn to be spent on new housing over the next two years, Mr Balls - who described himself as the "head and heart" candidate - said Labour had to show there was an alternative to "dangerous" cuts - based on supporting investment in the economy.
'Not in denial'
Andy Burnham, Health Secretary in the last government, said Labour could not afford to show it was "in denial" about tackling the deficit.
He said Labour needed to rethink its approach and had to make the "moral argument" for further tax rises to shoulder more of the burden than cutting spending.
Diane Abbott said Labour must "stand side by side" with the union movement against the cuts, which she said were "ideological not inevitable".
Politicians needed to better demonstrate the impact that cuts would have on private firms as well as the public sector, she added.
More than three million people - including approximately 270 MPs and MEPs, 160,000 party members and more than two million affiliated members - are entitled to vote in the leadership contest.
Chancellor George Osborne said on Monday that spending needed to be reduced to help "restore stability" to the economy and strikes would not be in the public interest.