Iraq's parliament confirmed it will meet today to amend the draft constitution after a deal proposing last-minute changes won support from at least one influential Sunni Arab group.
But opposition remained strong among other Sunni parties.
With three days left to a referendum, a parliament spokesman said parliament would begin its meeting at 7pm.
"There were meetings over the last few days. They reached results and we are waiting to put them to the National Assembly today for endorsement to assure the success of the constitution," said Muhand Abdul Jabar, media director for the speaker's office.
Officials in the ruling Shi'ite majority said four articles of the present draft constitution would be amended.
"There will be a vote on these four amendments," said Saad Qandeel, a member of parliament's constitutional drafting committee, adding that they would need a two-thirds majority vote -- a fairly easy hurdle for the ruling coalition.
Officials have said in the past that changes to the draft text distributed to voters can be advertised by television before Saturday's vote.
With Sunni opposition strong before the draft constitution goes to voters on Saturday, the Shi'ite- and Kurdish-led ruling coalition on Tuesday offered to discuss amending the charter after an election in December.
The deal, negotiated over three days in talks involving U.S. diplomats, would allow effectively allow the renegotiation of certain elements of the constitution in the first four months after a new parliament is voted in on December 15.
It won the support of the Iraqi Islamic Party, one of the more established groups among several claiming to speak for the once dominant Sunni Arab minority that largely boycotted January's election for the current interim government.