"It is up to the president to approve this decision," Abtahi told the student news agency ISNA, adding that President Mohammad Khatami -- who has a total of eight vice presidents in his cabinet -- should reach a decision soon.

News of Abtahi's intention to quit came a day after the now conservative-controlled parliament impeached the reformist transport minister, Ahmad Khorram, for mismanagement, corruption, a spate of accidents and favouring foreign firms in handing out government contracts.

Abtahi, a jovial and rotund mid-ranking cleric who is vice president for judicial and parliamentary affairs, has been one of the most outspoken members of Khatami's government.

But he said that working with hardliners, who took control of parliament in May after most reformists were barred from contesting February elections, had become impossible.

"For some time I have reached the conclusion that given the differences between my political viewpoints and those of the parliament, I cannot fulfil my responsibilities," Abtahi told ISNA.

"For this reason, I have since some time presented my resignation to President Mohammad Khatami so that the understanding between the government and the parliament can be improved," he said.

The vice president could not be immediately reached for further comment.

Government spokesman Abodallah Ramazanzadeh confirmed Abtahi had already discussed the issue with Khatami, but added that he did not know if the president -- currently on a tour of Algeria, Sudan and Oman -- had accepted the resignation.