The Conservatives are trying to exploit people's fears on immigration and asylum, Tony Blair has claimed in his first campaign speech on the issue.
Speaking in Dover, Mr Blair said concerns about immigration were not about racism but about fairness.
But he accused the Tories of waging a single issue campaign.
The Tories say the government should have done more over the last eight years. The Lib Dems say there is consensus for controlled immigration.
Conservative leader Michael Howard has made immigration one of his key election themes.
He claims the system is "out of control" and wants annual quotas for both immigration and asylum.
In a move against claims he has been bounced by Tory attacks, Mr Blair said he had long planned to make a detailed speech on the issue.
Acknowledging genuine concerns, Mr Blair said it was essential to be fair both to British taxpayers and to genuine asylum seekers and legal migrants who boosted the UK economy.
He argued it was vital immigration and asylum issues were not used to divide people or turn British tolerance on its head.
"I think most people know the huge contribution that immigrants have made to our country," he argued.
He attacked the way the Tories were raising the issue.
"It is an attempt deliberately to exploit people's fears, to suggest that for reasons of political correctness, those in power don't dare deal with the issue," he said.
The opposite was really true, he said.
Labour had cut asylum claims faster than anywhere else in Europe to the lowest level since March 1997, he said.
New controls, including a points system for economic migrants, more detentions and tagging for asylum seekers, were also planned by Labour.
Home Secretary Charles Clarke said Labour planned to recruit 600 new immigration officers to work at ports - a one in eight increase.
Mr Blair stressed that Britain was not a high immigration country compared with nations such as France, Germany or the USA.
David Davis accused Labour of sapping police morale
Nobody knew precisely how many people were in the UK illegally - something Mr Howard had admitted when he was home secretary in 1995, he said.
Mr Blair called the Tory policies "incoherent babble".
The Conservatives say they would use the UN refugee agency to fill asylum quotas and process all asylum claims overseas so people do not have to enter the UK illegally.
Anyone coming to the UK would be returned to regional processing centres: something Mr Blair branded a "fantasy island" policy.
Questioned on BBC One's Paxman interviews, Mr Howard said he could only start negotiations to set up the centres once in government.
Mr Howard defended his plan to withdraw from the 1951 UN Convention on Refugees, something done by countries such as North Korea and Saudi Arabia.
"I'm interested in doing the right thing for the people of this country," he said.
"I believe that we have to bring immigration under control, we have to limit the circumstances that people apply for asylum in this country."
The Tories say one speech from Mr Blair cannot put eight years of "pussyfooting" over a "chaotic" asylum and immigration system.
Liberal Democrat leader Charles Kennedy said: "All three political parties agree that we need a responsible, controlled immigration policy in this country."
He said the Lib Dems would create an independent commission to set quotas for economic migrants based on the needs of different sectors of the economy.
UK Independence Party leader Roger Knapman said a points system without a quota was pointless. He said Labour's decision "to 'talk tough' is nothing more than window dressing".
British National Party leader Nick Griffin said it was not racist to say there should be no more immigration.
Elsewhere, the Tories focused on tackling crime and drugs.
Mr Davis said the number of police officers quitting the service had doubled - something he blamed on the burden of paperwork sapping morale.
The Lib Dems highlight plans to tackle "ongoing discrimination" against women.
The party stressed proposals to make pensions for women fairer, guarantee a maternity income guarantee of £170 a week for new working mothers and introduce a "comprehensive" equality act.
Tory leader Michael Howard will appear in the Paxman Interviews on BBC One at 1930 BST on Friday. You can also watch the interviews live and on demand from the BBC News website.