The head of Iran's nuclear agency made the announcement but did not say when they would be ready to go into production at the Natanz atomic plant.
Centrifuges can be used to produce fuel for nuclear power and also to make nuclear weapons.
The announcement comes a few days before Iran enters fresh talks on its controversial nuclear programme.
"Our scientists have built a new generation of centrifuges, and cascades with 10 centrifuges each are now being tested," said Ali Akbar Salehi, head of the Atomic Energy Organisation of Iran, according to the semi-official Fars news agency.
Timing
Mr Salehi said the new centrifuges could enrich uranium with "more than five times the output capacity" of earlier centrifuges and Iran "plans to raise this capacity to 10 times", Fars reported.
The BBC's Tehran correspondent Jon Leyne, who is now in London, says it has been known for two years that Iran was working on upgrading this technology.
The fact that Iran made this announcement a few days before new talks might be seen either as a gesture of defiance, or perhaps as a way of Iran trying to increase its bargaining power, our correspondent adds.
Iran insists that its nuclear programme is for peaceful means, despite international concern that it is trying to develop an atomic weapon.
Six world powers are to hold talks with Iran in Geneva on 1 October.
