Tel Aviv expressed concern over the willingness to lift sanctions and allow billions in US dollars to flow into Iran in exchange for insufficient nuclear restrictions ahead of the Vienna discussions.
Israel is "very worried" that Iran will secure a windfall in sanctions relief in renewed nuclear negotiations with world powers but will not sufficiently roll back projects with bomb-making potential.
Prime Minister Naftali Bennett expressed Israel's concerns on Sunday ahead of the resumption of negotiations in Vienna.
"Israel is very worried about the readiness to remove the sanctions and to allow a flow of billions (of dollars) to Iran in exchange for unsatisfactory restrictions in the nuclear realm," Bennett told his cabinet in televised remarks.
"This is the message that we are relaying in every manner, whether to the Americans or to the other countries negotiating with Iran."
Negotiators will convene in Vienna on Monday in a last-ditch effort to salvage a nuclear deal, which the United States under then-President Donald Trump quit in 2018, reimposing sanctions on Iran.
That led to breaches of the deal by Tehran, and dismayed the other powers involved.
Upcoming nuclear talks
Israel, which is not a party to the talks, opposed the original 2015 pact as too limited in scope and duration.
Israeli leaders have long threatened military action against Iran if they deem diplomacy a dead end for denying it nuclear weaponry.
Tehran says its nuclear ambitions are peaceful.
Few expect a breakthrough in the talks as Iran's uranium enrichment activities have escalated in an apparent bid to gain leverage against the West.
Six rounds of indirect talks were held between April and June.
The new round begins after a hiatus caused by the election of a new Iranian president, Ebrahim Raisi, a hardline cleric.