"Gantz must think of ending the occupation instead of mobilizing his army to annex [the West Bank] and consolidate the occupation," Hussein al-Sheikh, the head of the PA General Authority of Civil Affairs, said on Twitter, Anadolu news agency reported.
Speaking to reporters on Wednesday, Gantz expressed his intention to directly negotiate with Palestinian President Mahmoud Abbas.
The Israeli government plans to hold a cabinet vote next week to annex parts of the West Bank, which was occupied by Israel during the 1967 Middle East war.
Israeli Prime Minister Benjamin Netanyahu has repeatedly said he would annex all settlement blocs and the Jordan Valley as of July 1 under an agreement with Gantz, the head of the Blue and White coalition.
The West Bank, including East Jerusalem, is seen as occupied territory under international law, thus making all Jewish settlements there – as well as the planned annexation – illegal.
Palestinian officials have threatened to abolish bilateral agreements with Israel if it goes ahead with the annexation, which will further undermine the two-state solution.
The annexation stems from US President Donald Trump’s "Deal of the Century", which was announced on January 28. It refers to Jerusalem as “Israel’s undivided capital” and recognizes Israeli sovereignty over large parts of the West Bank.
The plan states the establishment of a Palestinian state in the form of an archipelago connected through bridges and tunnels.
Palestinian officials say that under the US plan, Israel will annex 30-40% of the West Bank, including all of East Jerusalem.