By Parisa Hafezi and Tim Hepher

ANKARA/FARNBOROUGH, England (Reuters) - Iran has expanded its search for aircraft and is looking to order dozens more jets while it continues to try to overcome hurdles to deals worth some $50 billion with Airbus and Boeing, Iranian officials and Western industry sources said.

Iranian airline executives attended the Farnborough Airshow in Britain over the past week and held preliminary discussions with several potential sellers including Japan's Mitsubishi, which is developing a new regional jet, they said.

"Iran is planning to buy some 50 more airplanes of various types soon," an Iranian official said.

At the same time, Iran is continuing to meet Airbus and Boeing to try to resolve headaches surrounding the financing of existing deals to buy some 200 jetliners, needed to renew its fleet.

Earlier this year, the world's two largest planemakers struck provisional deals with IranAir under an agreement between Tehran and world powers to ease sanctions in exchange for curbs on Iran's nuclear activities.

"Yes, there are problems, financial and political, but there have been several meetings with Boeing and Airbus top authorities particularly in the past few weeks in order to resolve the issue and to find a way to overcome the remaining obstacles," an Iranian official close to the talks said.

Iran's Fars News Agency said officials from Airbus and the ministry of roads and urban development were due to discuss potential further plane purchases in Tehran on Sunday.

Airbus could not immediately be reached for comment.

Boeing representatives are also expected to visit Iran before the end of the month to discuss the mechanics of their tentative deal to sell or lease 109 jets to IranAir.

The U.S. House of Representatives this month passed a measure that could, if confirmed by the Senate and barring a presidential veto, block sales of Boeing and Airbus aircraft to Iran because they use a large number of U.S. components.

The latest contacts between Iran and Western planemakers come as questions hover over part of the $27 billion deal between Airbus and Iran, signed in January.

People familiar with the matter said recently that Iran was cooling towards the purchase of 12 A380 superjumbos that were part of the provisional deal.

Airbus subsequently announced a cut in A380 production.

"Some Iranian critics of the deal argue that we don't need big planes that will only be used by those traveling to America or similar destinations," a senior Iranian official said.

"We will evaluate that part when the time comes ... One solution is to buy around 50 other planes instead."

The official urged Western governments and manufacturers to help "resolve their side of problem, including the financing issue".

Asked what types of aircraft Iran could buy, he said, "It will be similar, but on a smaller scale, to what we have bought so far".

Many Western banks are reluctant to back the aircraft deals, fearing their money could be at risk if sanctions are restored.

The senior Iranian official said Italian and German banks had expressed interest in taking part, while aircraft industry sources say financiers in the UAE and China could play a role.

(Editing by David Clarke)