A draft text was finalised by members on Friday and will be voted on in New York on Saturday, diplomats said.
However, it is not clear whether Russia - which has vetoed two previous resolutions - will back the text.
Envoy Kofi Annan has called for a team to be deployed immediately to ensure compliance with his peace plan.
Several deaths were reported on Friday despite the ceasefire,
as thousands of protesters took to the streets across the country in
fresh revolt against President Bashar al-Assad.
Mr Annan's plan aims to end over a year of violence in Syria which has killed over 9,000 people, mostly civilians.
'Very tough'
In New York, efforts to draft a text were hindered by disagreements between Russia and the US, which prevented a vote on Friday.
Diplomats
revised a US-proposed draft on Friday to accommodate Russian
objections, but Moscow is still not certain to back the text.
Russia's permanent representative, Vitaly Churkin, told
reporters that there was "some good discussion" but he was not
"completely satisfied" with the talks.
The text was to be sent to governments for approval
overnight, and a vote is now expected at 11:00 local time (15:00 GMT) on
Saturday.
"There was a negotiation, there is not yet an agreement,"
French UN Ambassador Gerard Araud told reporters. "It's very tough, but
there will be a vote tomorrow in any case."
The resolution calls for the deployment of an advance team of
30 monitors. Additional approval will be required to increase the
deployment to 250, the total which Mr Annan is seeking.
A spokesman for Mr Annan has said that a small group of
observers is ready to leave for Syria as soon as a resolution is passed.
"At the moment we have the advance team standing by to board
planes and to get there, to get themselves on the ground as soon as
possible," Ahmad Fawzi said.
Earlier, President Barack Obama authorised an increase in US
aid for Syria's "non-violent, political opposition", including
communications equipment and medical supplies, officials said.
Shelling and shooting
On Friday, anti-government demonstrators in Syria poured out
of mosques after Friday prayers in many areas, amid tight security
precautions.
"We tried our best to reach Assi Square in order to
show the world the truth about the regime - they are lying and will not
allow us to have big, peaceful demonstrations," Mousab Hamadee, an
activist in Hama, told the BBC.
"As we approached Assi Square, they started opening fire on us. Two of my colleagues were martyred," he added.
The Local Co-ordination Committees (LCC), an activist
network, said security forces had killed 13 people, including in Deraa,
Hama and Idlib.
Activists have also said there has been a resumption of bombardments in Homs, although not on the same scale as before.
The state news agency, Sana, said an army officer was killed
when a bomb exploded next to a military bus in Aleppo, and that a Baath
Party official had been shot dead in Deraa province.
The BBC's Jim Muir in Beirut says the overall casualty
figures for Friday, though they may be revised upwards, were very much
lower than many had feared.
In general, he says, the ceasefire has brought a sharp drop
in the level of violence and deaths but, with troops, tanks and heavy
weaponry still deployed in and around population centres, it is still
very fragile.
Source: BBC News