A new police force charged only with securing Britain's borders would be created under Conservative plans.
The new force would bring together current agencies
The new force would bring together officers from Customs and Excise, the police and immigration currently working at ports and airports.
Tory leader Michael Howard said Labour had "totally failed" to enforce the controls needed to limit immigration, fight crime and prevent terrorism.
Labour says it is tightening controls. Lib Dems also want a new border force.
Internal surveys by the Tories and Labour suggest that immigration and asylum are key issues for the electorate with the potential to swing large numbers of votes.
Mr Howard publicised the new proposals as he tried to shift attention away from the row over his decision to sack Tory MP Howard Flight.
"Our immigration system is being abused - and with it Britain's generosity," he said.
He pointed to reports that immigration officials allow people with fake or suspect identity papers to enter Britain for 48 hours - instructing them to return later for questioning or deportation.
Mr Howard said: "Does anyone seriously imagine that someone with the clear intent to inflict harm or terror in Britain would turn up? It's hard to imagine a laxer system.
"We face a real terrorist threat in Britain today - a threat to our safety, to our way of life, and to our liberties.
"But we have absolutely no idea who is coming into or leaving our country."
Mr Howard said the new police force would mean there was "one face at the border" with a clear line of accountability.
There are 7,400 officers from Customs, Special Branch, ports police and immigration working on British border controls.
Shadow home secretary David Davis said the "main components" of those officers would become part of the new police force.
Before it was created "tens of millions" would be spent ensuring 24-hour surveillance at ports, he said.
The Police Service of Northern Ireland would continue to police the land border.
The Tories also want biometric visas to be used by people coming from all non-European Union countries which are sources of illegal immigration.
The party has already unveiled plans for annual limits on immigration and asylum and a points system for work permits.
The Lib Dems announced their plans for a national border force last year.
A spokesman said the current system, where different agencies enforce border controls, was a recipe of confusion.
"We think a lot of the problems of immigration are about the way the system is administered, now having posturing about how tough you are," he said.
'Collapse in credibility'
For Labour, Immigration Minister Des Browne accused the Tories of "playing with" immigration, while Labour dealt with it.
He said the Conservative policies were uncosted and unworkable and illustrated a "complete collapse in Tory credibility".
"Now they expect the public to believe that they can make new spending commitments on borders, whilst also promising to cut the immigration and asylum budget in half, alongside their plan to cut £35bn from public spending," he said.
The Conservatives say they will save money by cutting asylum claims.
The UK Independence Party said the Tory plans were "worthless" because a British border police force could only enforce what the European Union allowed it to enforce.