Shtayyeh also said Trump and Netanyahu were using the announcement of the plan as a distraction from their domestic woes.
Aaron David Miller, a Mideast expert with the Carnegie Endowment for International Peace, said Kushner's team wants to "finally, basically demonstrate that they have a plan" - and to do so ahead of the USA presidential election.
Despite this apparent economic incentive, Palestinian leaders have made clear that they no longer recognize Washington's historic role as mediator in the conflict, given Trump's repeated backing of Israeli demands. In fact it's overly good to them.
Although the details of what is in the White House peace plan have yet to be released, it is expected to be more favorable to Israel than any previous USA proposal.
The Oslo Accords resulted in Israel's recognition of the Palestine Liberation Organisation (PLO) as a representative of the Palestinian people and a party to the peace negotiations. Instead, he said the friendly Trump administration was providing Israel a once-in-a-lifetime opportunity that must be seized.
Trump has already thrown Netanyahu a string of political presents.
That would effectively move the USA -recognized Israeli border further east into Palestinian territory and Israeli sovereignty would be recognized over the whole of Jerusalem, which Palestinians seek as the capital of their future state.
The Trump administration took several steps in recent years that angered the Palestinians.
"They say that's the hardest of all deals".
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Now, 15 Chinese cities in Hubei province, of which Wuhan is the capital, are in lockdown, impacting more than 57 million people. State-run news media posted photos of the first hospital under construction, with swarms of bulldozers smoothing a dirt field.
But according to sources, Gantz was reluctant to be seen at the White House alongside Netanyahu.
Trump first announced his "deal of the century" immediately after he was voted into office in 2016, in an interview by The New York Times on November 23.
"Note that the 28th [of January] was the date of the Knesset's immunity vote on Netanyahu's corruption charges", she said on Twitter.
"There is reason to fear that a prime minister with three indictments against him will make decisions based on the personal interest of his own political survival".
As the White House prepares to unveil its long-awaited plan for a peace deal between Israelis and Palestinians, CNN has learned that the Trump administration has renewed its attempt to speak to Palestinian Authority leader Mahmoud Abbas.
Political ties between Palestine and the USA were severed immediately after Trump declared Jerusalem as the capital of Israel in 2017 and moved the American embassy to the city in 2018.
But it could give Mr Netanyahu, who is in the middle of his third re-election campaign in under a year, a boost as he tries to remain in office while fighting criminal charges of fraud, breach of trust and accepting bribes.
Netanyahu has said he plans to annex the Jordan Valley as well as Jewish towns across Judea and Samaria, which would all but extinguish any possibility of creating a viable Palestinian state.
Trump has delivered political favours to Netanyahu during the previous two races as well, only to see his friend fall short of victory.