Negotiations for transparency of Tehran's nuclear drive with the UN nuclear watchdog have been postponed until February while Iran and world powers prepare to implement a landmark nuclear deal, officials said Tuesday.

Talks with International Atomic Energy Agency experts, which are also examining long-standing allegations of past nuclear weapons research by Tehran, were originally scheduled for January 21 in the Iranian capital.

But "the next round of talks has been postponed to February 8 as preparations are underway for (implementation) of the steps agreed in Geneva," Iran's envoy to the IAEA, Reza Najafi, told the ISNA news agency.

Najafi was referring to the deal Iran and the so-called P5+1 group agreed in the Swiss city in November that will temporarily curb Tehran's nuclear drive in exchange for modest sanctions relief.

An IAEA spokeswoman in Vienna, Gill Tudor, confirmed to AFP the date of the new round.

In the meantime, Iranian nuclear officials said IAEA experts will visit Tehran on January 18 to prepare the implementation of the Geneva deal that is to come into full effect two days later.

Under the accord, Iran must limit its enrichment of uranium to five percent for six months and begin to neutralise its stockpile of uranium purified to 20 percent, a few technical steps short of weapons-grade material.

These steps need to be monitored and validated by IAEA inspectors.

In Vienna, Tudor did not comment on the experts' possible visit to Iran, but said "the necessary preparations will be made for implementation" of the deal with the P5+1 group (Britain, China, France, Russia, the United States and Germany).

On November 11, Iran and the IAEA agreed a framework deal that included six practical steps that Tehran would take by February 11.

The first was a short visit to the heavy water plant at the unfinished Arak reactor that took place on December 8, when all of the IAEA's "technical objectives" were met, according to the Vienna-based agency.

The second is a visit to the Gachin uranium mine in southern Iran -- off-limit to IAEA inspections since 2005 -- that is yet to be arranged but must take place before the February 11 deadline.

The others include providing information on future research reactors, identifying sites designated for new nuclear power plants, as well as clarification on Iranian statements regarding additional enrichment facilities and laser enrichment technology.

The IAEA talks are running in parallel with the P5+1 negotiations, and seek to increase transparency on Iran's ongoing nuclear activities and shed light on its past efforts of alleged weaponisation of its drive.

Western powers and Israel suspect Iran's nuclear programme is masking military objectives. Tehran has repeatedly denied that charge, countering that the Islamic republic only seeks peaceful applications of the technology.

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