The UN General Assembly will vote on September 10 on the measure that is almost certain to garner a majority of votes in the 193-nation forum.
"We have the votes and we are working to get as many votes as we can," said Riyad Mansour, the Palestinian representative to the United Nations.
Once adopted, the UN will have 20 days to carry out the decision, which would be in time for Abbas' visit on September 30.
"It is a symbolic thing but it is another step to solidify the pillars of the state of Palestine in the international arena and give our people a small hope that the international community is still supporting the independence of the state of Palestine," Mansour told reporters.
The draft resolution presented last week to the General Assembly would allow the flags of Palestine and of the Holy See to be hoisted alongside those of the 193 member states.