The P5+1 countries, comprising Russia, China, the United States, the United Kingdom, France and Germany, agreed with Iran on a number of key issues that include uranium enrichment, the number of centrifuges and sanctions imposed on the Islamic Republic.
"The cabinet is united in strongly opposing the proposed deal," Netanyahu said.
The prime minister said the deal would, against international negotiators' belief, legitimize Iran's nuclear program, leaving the country with a vast nuclear infrastructure.
He added that the deal came at the time when Iran was stepping up its "aggression and terror" in the region and beyond.
A comprehensive deal on Iran's nuclear program is expected by the end of June.