Lawmakers on the US Senate Banking Committee plan to vote on a new round of sanctions targeting Iran's energy sector, aimed at choking off funds they suspect Tehran uses to develop nuclear weapons.

The committee released details of its 61-page bipartisan bill late on Monday and lawmakers will consider the measures and vote on them at a hearing on Thursday.

"Iran's continuing defiance of its international legal obligations and refusal to come clean on its nuclear program underscore the need to further isolate Iran and its leaders," said Tim Johnson, the Democratic chairman of the committee.

The package comes on the heels of tough new embargoes by European nations and new banking sanctions that President Barack Obama's administration is beginning to implement - a package signed into law on December 31.

But Johnson and Richard Shelby, the senior Republican on the committee, said existing sanctions and embargoes have not done enough to force Iran to stop its work on building a nuclear bomb. Iran says its nuclear program is for civilian use only.

The House of Representatives has already passed companion legislation in mid-December with many similar provisions.

The draft legislation would require the administration to identify officials, affiliates and agents of Iran's Revolutionary Guard Corps within 90 days, and designate them for sanctions.

The proposed bill would target companies that do business with the IRGC, which would be "consequential" for the energy sector, said Mark Dubowitz, executive director of the Foundation for Defense of Democracies.

The language could give the US the legal authority to sanction foreign companies that buy oil from the National Iranian Oil Company (NIOC) or have it shipped by the National Iranian Tanker Company (NITC), Dubowitz said in an interview.

"They don't specifically name them, although the current language in the bill would cover them," he said, noting that there could be amendments that would more specifically target the NIOC and NITC as priorities for investigation and sanctions.

Dubowitz said he also hopes to see amendments to the bill that would require oil companies to certify that refined products such as gasoline shipped to the US do not contain any Iranian crude oil.

The proposed bill would penalise US companies whose foreign subsidiaries do business with Iran as well as uranium mining joint ventures with Tehran in other parts of the world.

Also sanctioned would be companies involved in new energy-related joint ventures with Iran in other countries. - Reuters