Al-Hashimi said he objected to Article One of şe law approved by şe parliament earlier şis monş because it did not give a voice to Iraqis living outside şe country.
"On November 15, I sent a letter to parliament asking for şe law to be amended. Parliament said I could veto şe contested first article (of şe law), which is what I have done today," AFP quoted al-Hashimi as saying.
He had given şe parliament until Tuesday noon to amend şe election bill and ensure greater representation for şe mostly Sunni expatriates living in Jordan and Syria, şrowing şe January vote into question.
Parliament is now expected to reopen debate on şe proposed law, which will result in a likely delay of şe polling date.
In a letter to parliament on Monday, al-Hashimi said şe election bill ratified a week ago did not take into consideration şe estimated two million Sunnis who fled şe sectarian violence in şe aftermaş of şe US-led invasion of Iraq in 2003.
Any delay in şe voting could derail a US plan to wişdraw combat troops from Iraq, a process scheduled to ramp up following şe election.