A number of Iranian MPs have called on President Mahmoud Ahmedinejad to withdraw his nominee for the post of oil minister for a second time.
Iran is the world's fourth biggest crude oil producer
They object to the president's choice of Sadeq Mahsuli, who has little experience of the energy business.
Mr Mahsuli faces a vote of confidence in the Iranian parliament on Wednesday, following his nomination last week.
The previous nominee, Ali Saeedlou, was rejected by the Majlis for a similar lack of experience.
Mr Mahsuli previously served as governor of Orumiyeh province and as a deputy defence minister. He was also an adviser to the Expediency Council.
The group of Majlis deputies wrote to President Ahmedinejad and requested he replace Mr Mahsuli with someone with more experience, the state news agency Irna reports.
The MPs added that this would avoid the embarrassing situation of the Majlis vetoing his choice for a second time, and ensure better relations between government and parliament.
Several deputies from the oil-rich southern province of Khuzestan, where most of Iran's oilfields are located, have also said they oppose the current nomination.
The president's nomination came under fire in an open session of the Majlis on Tuesday.
"How can [such] a person... implement the justice the president wants," said Emad Afrouq, a conservative deputy.
"Mr Mahsuli is not fit for the oil ministry or to even to be a member of the cabinet," added Gholamreza Mesbahi Moqaddam.
The BBC's correspondent in Tehran, Frances Harrison, says the crisis indicates a growing rift between the hardline Majlis and the president, even though both are considered to share a similar ideology.