Iran currently uses around 3,000 'P-1' centrifuges, according to the UN nuclear watchdog, the IAEA, that are prone to breakdown when working at high speed for long periods.
Iranian authorities have repeatedly said the country needs 50,000 centrifuges to provide its annual requirements for nuclear fuel.
Russia is completing the construction of Iran's first nuclear power plant, Bushehr in the Islamic Republic's south.
Iranian President Mahmoud Ahmadinejad announced tests on advanced nuclear equipment on Tuesday - Nuclear Technology Day in Iran - also adding that the country had started to install another 6,000 'ordinary' uranium enrichment centrifuges at its underground facility in Natanz.
Ahmadinejad did not specify the type of equipment, but it is believed he was referring to 'P-2' model centrifuges, which are more reliable than the ones Iran currently uses. The 'P-2' is capable of enriching uranium to weapons-grade level.
The announcements apparently signal that Iran has no interest in taking steps to avoid a third set of UN Security Council sanctions over its defiance to halt uranium enrichment, used both in weapons and electricity production.
A resolution on a third set of sanctions was adopted in late February and will come into force when a 90-day deadline expires.
Tehran has repeatedly rejected international demands to halt uranium enrichment, insisting it needs the process to generate electricity.
