LONDON - (Dow Jones)- Under pressure to appoint an oil minister by the end of November, Iranian President Mahmoud Ahmedinejad will submit a list of nominees to parliament by the end of this week, Iranian government and industry sources said Tuesday.

But they warn the process could be subject to further delays, as different Iranian political groups continue to back their favored candidates for Iran's top oil post.

Back in August, parliament rejected Ali Saedlou, the president's number one choice for oil minister.

Iranian oil officials say among the four candidates on Ahmedinejad's latest list are Kazem Vaziri-Hamaneh, who is currently acting as caretaker of Iran's oil ministry; and Ali Beheshtiyan, an oil man who has been heavily involved in the development of Iran's southern oil fields.

But Ali Ghezelbash, with Tehran-based Atieh Bahar Consulting says, "We can't judge who will be appointed by whose names are on the president's list."

"The President may struggle to get his chosen candidate because of the various power struggles going on in Iran," he said.

Iranian oil sources say Vaziri-Hamaneh is being supported by technocrats in the oil ministry, while Beheshtiyan has the support of politicians in the south of Iran.

Under Iranian law, parliament is given one week to assess the list of nominees. It will then decide to whether grant a vote of confidence.

Iranian oil officials say the appointment of a minister is vital for negotiations to proceed with foreign oil companies eager to participate in Iran's oil sector.

"Things are very much on hold at the moment as many officials within Iran's oil ministry are unsure of their positions, while foreign companies are just treading water," said one Iranian oil executive.

Foreign investment is key if Iran, the Organization of Petroleum Exporting Countries' second largest producer, is to realize its ambition to increase crude production from around 4 million barrels a day to 5 million b/d over the next two years.