Reuters- Total (TOTF.PA) is in talks to buy a multi-billion dollar stake in Iran's partly-built liquefied natural gas (LNG) export facility, Iran LNG, seeking to unlock vast gas reserves.

The French oil major -- the first of its peers to strike deals in Iran after sanctions -- seeks entry into Iran LNG at a discount to the pre-sanctions price in exchange for reviving the stalled project, two sources with knowledge of the matter said. A third source confirmed Total was in the running for a stake, alongside several other oil majors, but any deal was still some way off.

Total declined to comment. Iran's National Gas Export Co. (NIGEC), a central stakeholder in the project, did not respond to requests for comment by email and phone.

"Iran is trying to revamp its oil and gas projects and the abandoned LNG plant is one of them," the third source added.

Iran shares the world's biggest gas field with Qatar, which has used the reserves to build over a dozen giant liquefaction plants to chill gas into a liquid for export on ships -- a move Iran is keen to replicate.

The Iranian part of the field, known as South Pars, contains over 14 trillion cubic metres of gas, according to the Pars Oil and Gas Company website.

Iran aims to grow gas output to 1 trillion cubic metres by 2018, up from 160.5 billion cubic metres in 2012, before the latest sanctions took effect.

But it currently has no ability to freeze its gas into LNG for tanker exports.

However, Total aims to commit $2 billion to develop the 11th phase of the South Pars field this summer - supplies from which could be used to feed Iran LNG - though that investment hinges on the renewal of U.S. sanctions waivers.

Any deal for a stake in Iran LNG would also likely face similar hurdles.

An Iranian industry source with ties to Iran LNG said Total moved several employees to the firm's offices in Tehran last year as part of the discussions.

Work on the 10.8 million-tonnes-per-annum (mtpa) plant hit a wall in 2012 when sanctions stopped Iran from bringing in specialist liquefaction technology from German contractor Linde (LING.DE).

The Munich-headquartered firm declined to say when it would ship the parts to Iran. At issue are reimbursements demanded by Linde for the cost of storing Iran LNG's liquefaction train, or production line, during the sanction years, industry sources said.

"Equipment was finished for the first production line (or train) of 5.4 mtpa, and about half finished for the second one," a second Iranian gas industry source said.

With $2.3 billion invested so far, Iran LNG is more than half-built with two storage tanks, a jetty and power plant, sources said -- but total costs to bring the plant on-stream may be as high as $10 billion.

NIGEC, which owns 49 percent of the joint venture, and Iran Oil Pension Fund, which holds the rest, have expressed willingness to sell down their stakes to attract a Western partner.

(Editing by Ruth Pitchford)