(BBC) -- Prospects of holding elections in Iraq in January have again receded after MPs amended a law without addressing the concerns of one of its vice-presidents.

Tariq al-Hashemi, a Sunni Arab, vetoed a previous version of the election law because he wanted more representation for millions of Iraqis living abroad.

Sunni MPs opposed Monday's amendments, which would see more seats allocated to Kurds in the north and fewer to Sunnis.

Mr Hashemi is expected to veto the law again and send it back to parliament.

Analysts say that even if the law is eventually approved, it now looks unlikely this will happen in time for elections to be held by the end of January, as required by Iraq's constitution.

The vote is seen as a prerequisite to the US meeting its goal of pulling out combat troops by August, and withdrawing fully by 2011.

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The BBC's Jim Muir in Baghdad says the Iraqi Council of Representatives had to solve two problems - one was the issue raised by Mr Hashemi's veto; the other was a threat by the Kurds in the north to boycott the election because they regarded the number of seats they had been allocated as unfair.

Compromise solutions were agreed by the main Shia factions and the Kurds, and later passed with a substantial majority, our correspondent says.

They agreed that voters outside Iraq should be able to vote for candidates in their own provinces, as if they were still at home.

To meet the Kurdish complaint, they agreed that populations in the provinces, which act as constituencies, should be based on food ration data from 2005, when the last election was held, and deemed to have increased at a rate of 2.8% per year.

That would give the Kurds more seats than the bill passed by parliament earlier this month and vetoed by Mr Hashemi, but also mean that predominantly Sunni areas would lose some of the extra seats they had been given, our correspondent says.

The amendments also failed to increase the representation in parliament of displaced people from 5% of the total to 15%, as Mr Hashemi had demanded.

"This has widened the problem and we are heading into a dark tunnel," Alaa Makki of the Sunni Accordance Front told the Reuters news agency.

Mr Hashemi is therefore expected to veto the amended law and send it back to parliament. Parliament can, however, override a second veto with a three-fifths majority.

Our correspondent says most MPs seem to be determined to reject the veto this time, meaning the law should eventually go through.

But at the moment, it looks unlikely to happen in time for parliamentary elections to be held in January as planned, he adds.

After Mr Hashemi's first veto, the Independent Electoral Commission of Iraq said it required 60 days notice to prepare for the vote.