"The sanctions on Iran are working. They are very strong; they are a moment away from achieving their goal," he said ahead of the weekly cabinet meeting.
"The sanctions must not be eased before reaching the goal of dismantling Iran's enrichment capability -- the ability to produce nuclear weapons," Netanyahu said.
Netanyahu met US President Barack Obama last week at the White House for talks over Iran's contested nuclear programme, and then delivered an uncompromising speech on the topic at the United Nations General Assembly.
"Iran claims that it wants this for peaceful nuclear energy purposes," said Netanyahu.
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"Seventeen countries produce nuclear energy for peaceful purposes without even one centrifuge... And without enrichment because enrichment is a main process in producing fissionable material for nuclear bombs."
The next round of talks with the so-called P5 +1 -- the United States, Britain, France, China, Russia and Germany -- is scheduled to take place in Geneva on October 15 and 16.
Those proposals required Iran to suspend enrichment of uranium to the 20 percent level it says it needs for a medical research reactor and halt enrichment at its underground plant at Fordo near the central city of Qom.
The US and its allies suspect Iran of striving to develop nuclear arms under the cover of its civilian nuclear programme, a charge Tehran vehemently denies.