Kemi Badenoch has urged the Government to make it more difficult for immigrants to secure permanent residency or a UK passport.
Immigrants should only be able to apply for British citizenship after being in the UK for 15 years rather than the current six, the Tory leader said.
Ms Badenoch said: “The Conservative Party is under new leadership. We’re going to tell the hard truths about immigration.
“The pace of immigration has been too quick and the numbers coming too high for meaningful integration. We need to slow down the track for citizenship. A UK passport should be a privilege not an automatic right.”
This is one of the first policy announcement since Mrs Badenoch became leader.
The Conservatives also called for new conditions to be imposed on anyone applying for indefinite leave to remain.
This would include applicants having to show they had never claimed benefits or used social housing, had no criminal record, and would be a “net contributor” to the UK economy.
Mrs Badenoch refused to put a figure on how much her proposal would cut immigration by, saying only it is “the right thing to do”.
But Dame Angela Eagle, the minister for border security, said the Conservatives had “lost control of our borders” during their 14 years in power.
She said: “After 14 years of shameful Tory failure no one will take seriously anything they claim or promise now.
“Many of the things they are saying already exist or are the reversal of policies they introduced themselves in recent years, a sign of how chaotic they are.
“They had 14 years to get a grip of the system and instead they created chaos which Labour is now clearing up.”