A future Tory government would consider making forced marriages a criminal offence, David Cameron has said.
David Cameron believes thousands of forced marriages take place
The Conservative leader committed his party to a series of measures against a practice which he branded "utterly bizarre and frankly unacceptable".
These include ensuring people coming to Britain to get married are at least 21.
About 300 cases a year are reported to the government's Forced Marriage Unit but Mr Cameron believes this is merely "the tip of the iceberg".
He used a visit to Bradford to meet victims of forced marriages, as well as to hold a meeting of the shadow cabinet.
Mr Cameron stressed the measures did not apply to voluntary arranged marriages, which often resulted in long and happy unions.
"Forced marriages, on the other hand, are the practice where girls - some as young as 11 - are bullied, psychologically pressured, assaulted, sometimes kidnapped and taken abroad, and forced to marry someone they don't want to," he said.
The current Forced Marriages Act allows victims to take action only under civil, not criminal, law.
"The argument runs that it is unlikely that victims will come forward if it means pressing criminal charges against their parents," Mr Cameron said.
"But we shouldn't close this door - and if the current legislation doesn't work in ending forced marriages, the Conservative Party would consider making them a criminal offence."
He said it was important to ensure existing law was applied properly, because many of the methods used to force women into marriage - threats, assault, rape and kidnap - were already crimes.
Among the Tories' suggestions are "awareness packs" which would teach schools how to deal with children whom they suspected had been taken, or were likely to be taken, abroad for forced marriages.
And anyone wishing to marry abroad would have to register the names of themselves and their spouse-to-be, as well as a deadline for a wedding to be held.
In a separate move, the party has said it would require anyone coming to live in the UK to have a basic command of English.