StatoilHydro is currently developing part of the South Pars project to tap Iran's biggest single gas deposit but put other investment plans on hold last year amid rising tensions between the west and Tehran over Iran's nuclear programme.
Early signs of thawing relations between Tehran and the U.S. Obama administration after years of isolation under George W. Bush, is encouraging but investors remain wary.
"There might be signs that things are changing … (But) it's much too early to say how this is going to go," Peter Mellbye, Statoil's vice president of International Exploration and Production, told journalists in London late on Wednesday.
"We are going to fulfil the contractual obligations that we have to South Pars but we are not intending to expand our activities in any way until the political situation has changed."
U.S. firms are banned by the U.S. government from investing in Iran because Washington suspects Tehran's nuclear programme is aimed at making weapons, not just energy as Iran says.
Major European energy firms are keen to tap the world's second largest gas reserves but have shied away from investing the huge sums required under pressure from their own governments and Washington.
French oil major Total, which has a memorandum of understanding with Iran to develop part of South Pars, said on Thursday the investment terms were not attractive enough. (Reporting by Daniel Fineren; editing by James Jukwey)
