Many Iraqi politicians are also sceptical of effectively approving the presence of US troops in the country, alongside concerns that Baghdad should have more control over a foreign force that has previously operated outside Iraqi law.
Baghdad had previously said that the draft security pact, which was agreed last week after months of negotiations with Washington, was unlikely to be renegotiated.
But Hoshyar Zebari, the Iraqi foreign minister, had already acknowledged that parliament was "unlikely" to approve the so-called Status of Forces Agreement (Sofa) before the US presidential elections on November 4.
"Because of the differences among the political groups, we don't believe the deal will be approved now. Iraq still hopes to sign this deal before the end of the year,' he said.
"We knew it was going to take a little while to get this done"
White House spokeswoman
Iraq's Political Council for National Security reviewed the agreement on Sunday and Monday this week before sending it on the cabinet. If the pact gets government backing it will then be laid before the 275-member parliament for approval.
The cabinet decision came just hours after Michael Mullen, chairman of the US Joint chiefs of staff, warned that time was running out for Baghdad to back the deal, which was originally due to have been completed by the end of July.
He warned that when the current UN mandate runs out on December 31, Iraqi security forces "will not be ready to provide for their security".
Mullen said Iraq risked security losses of "significant consequence" unless it approved an agreement that provides a legal basis for US forces to remain in the country.
But the Bush administration on Tuesday played down the cabinet's decision to seek further negotiations.
"We knew it was going to take a little while to get this done," Dana Perino, the White House spokeswoman, said. "We knew that the Iraqis would have several steps to go through."
Al-Dabbagh said that Iraqi leaders were "still hesitant to approve or reject" the deal and that only the main Kurdish groups supported the pact without any requests for revisions or reservations.
He said the format for bringing US soldiers to trial if they committed crimes within Iraq had proved to be one of the key stumbling blocks to passing the deal.
The current draft is understood to allow Iraq to try American troops for serious crimes committed while off-duty and off base, something Iraqi officials have described as a major concession from Washington.
Washington has also agreed to withdraw its combat forces from Iraqi towns and cities by June 2009 with a complete pullout in 2011, eight years after the invasion that forced Saddam Hussein, the former president, from power.
Humam Hamoudi, a leading member of the ruling Shia alliance, said that Nuri al-Maliki, the Iraqi prime minister, was among those who had voiced doubt about the deal in recent days.
"The prime minister said:'what [the Americans] have given with the right hand they have taken away with the left hand'," Hamoudi told a news conference.
"For example, they said the US forces will withdraw from towns by June 2009 if the security situation permits that. But who will decide that?"