Muhammad Shtayyeh, a member of the Palestinians' U.N. contingent, said the date would be announced Tuesday by Arab League Secretary-General Nabil al-Arabi in Cairo after a meeting of Arab foreign ministers, Palestinian news agency WAFA reported.
The Palestinians have more than enough votes to guarantee passage of the membership resolution, he said. Passage requires 50 percent of the 193 member U.N. nations plus one.
Shtayyeh said there will be no turning back, a point made Sunday by Palestinian Authority President Mahmoud Abbas, WAFA said.
"We have the full backing from Arab and Islamic countries and from the Non-Aligned Movement," Shtayyeh said.
"The train has left the station. This is a point of no return from our side."
Shtayyeh said U.S. President Barack Obama failed to convince Abbas to hold off on the application when they talked Sunday. He said he didn't expect any serious retribution from the United States or Israel as a result of going forward in seeking the U.N. vote, WAFA said.
"I find it extremely shocking that the U.S. and Israel would oppose this step," he said.
"What did we do to deserve this punishment? Did we declare war?"
He said the goal of the U.N. bid is to gain recognition of Palestine within the 1967 borders, though the resolution is worded to allow negotiated changes.
He said the bid will protect the two-state solution and give credence to negotiations.