United States officials have outlined plans to train and equip more than 50,000 peacekeepers over the next five years, mostly for deployment in Africa.
UN peacekeepers are deployed in several African trouble-spots
The idea is expected to be announced at the Group of Eight (G8) summit of the world's richest countries in the US.
The initiative had grown out of African requests for assistance in ending civil wars, the officials said.
State Department official Glyn Davies said the plan was not intended to supplant the work of the UN.
But he pointed to the UN's failure to prevent the 1994 genocide in Rwanda as an example where a rapid peacekeeping response could have saved lives.
He said peacekeepers need to react speedily in the early stages of crises - and "very often that is before the United Nations has actually come together and issued a mandate."
More than 30,000 UN peacekeepers are deployed in Liberia, Sierra Leone, Democratic Republic of Congo, Burundi, Ivory Coast, Ethiopia, Eritrea and Western Sahara.
Last week, there were anti-UN riots in DR Congo, when the peacekeepers did not intervene to stop rebels capturing the town of Bukavu.
"We do a better job today I would say of peacekeeping and getting together the resources to do it than we did, say, 10 years ago," Mr Davies said.
But he said the peace missions were not as well organised as the US would like.
US President George W Bush would ask congress for $600m to train and equip the peacekeepers, other official said.
Italy is expected to offer training facilities at a police college, while other G8 members will offer funding and logistical support, the officials said.