ANKARA: Iran has canceled a London conference where it was set to introduce new oil and gas contracts to investors, the Seda weekly reported on Saturday citing a senior Iranian official who blamed a delay in getting visas.

Postponed five times amid uncertainty over international sanctions against Iran which were lifted this month, the conference had been set for Feb. 22-24.

Foreign companies will now be invited in May to bid for the new Iran Petroleum Contracts (IPCs), Ali Kardor, deputy head of the National Iranian Oil Co. (NIOC), told the weekly.

"The London conference has been canceled because the British Embassy in Tehran could not issue visas for representatives of Iranian companies as its visa section has yet to become active," Kardor said.

"There will be bids in May for new contracts ... There will be no need to hold a conference abroad after the bids," he said.

To bolster its economy, Iran is sweetening the terms of its oil development contracts to lure back international companies.

Some 135 firms, including BP, France's Total, Italy's Eni and Spain's Repsol attended a conference in Tehran in November to hear about the IPC.