The move, on Wednesday, comes as the International Atomic Energy Agency (IAEA) meets in an emergency session to decide on a resolution after Iran resumed uranium conversion activities at the plant on the outskirts of Isfahan.
"The rest of the seals will be removed today and the activities will resume," Gholamreza Aghazadeh, the head of Iran's atomic energy organisation told state television.
Iranian officials are expected to remove the seals placed on machinery by the IAEA in November when Iran suspended conversion, but under the watchful eye of the UN body's inspectors.
Throughout the current escalation of tensions, Iran was emphasising it was resuming conversion activities in concert with the IAEA, whose inspectors have installed surveillance equipment to monitor the process.
The breaking of the seals, as well as having important symbolic value, also means the Isfahan plant is able to work at full capacity.
The resumption of conversion had until now only been partial as Iran was waiting for the inspectors to finish installing surveillance cameras.
President Ahmadinejad said the
EU offer was insulting to Iranians
Conversion turns uranium ore or yellowcake into a feed gas for enriching uranium, which can be the fuel for reactors or the explosive core of atom bombs.
Iran's decision to resume conversion activities sparked concern in European capitals that have been locked in months of tortuous talks to persuade Iran to renounce ultra-sensitive nuclear activities.
However, Iran emphasises that its right to the nuclear fuel cycle is legally enshrined under the nuclear Non-Proliferation Treaty and its suspension of conversion was merely a goodwill gesture during talks with the Europeans.
The country has been under investigation for more than two years by the IAEA, which has accused it of hiding controversial nuclear work but has yet to find any proof of a weapons programme.
More talks likely
President Mahmood Ahmadinejad has described the offer of nuclear, commercial and political cooperation made on Friday by the Europeans in exchange for Iran renouncing the activities as an "insult to the Iranian people".
"The Europeans talk as though the Iranian people were a backward people, as if they were still in the last century when they dominated our country," he added.
But while Ahmadinejad's comments published on Tuesday appeared to confirm Western fears he will adopt a tough line on the nuclear issue, he also emphasised he was leaving the door open for more talks with the Europeans.
"The Europeans talk as though the Iranian people were a backward people, as if they were still in the last century when they dominated our country"
Ahmadinejad has yet to appoint a new government, but one of the candidates for the post of foreign minister - parliamentary foreign affairs committee head Aleaddine Boroujerdi - made clear there was no going back from the move.
The best guarantee that Iran's nuclear programme is peaceful is the "infallible watching of the IAEA cameras," he said. "I hope that the Europeans will also accept this reality."
He added that the regime still had not made any decision on restarting Iran's uranium enrichment plant in the city of Natanz.
Enrichment remains suspended, but officials emphasise this is only temporary.