"I am determined to address Congress, that is why I decided to go to Washington and present Israel's position," Netanyahu told participants at an election event by his Likud party.
The White House has already voiced concern over the premier's speech, and it announced Friday that US Vice President Joe Bien would not attend the address.
President Barack Obama said he will not meet Netanyahu during his visit, which comes a few weeks before the prime minister seeks re-election. The speech before Congress is expected on March 3.
Obama's allies fear the trip could be used by Israel and by US Republicans, who control Congress and issued the invitation, to undercut ongoing nuclear talks with Tehran.
The West and Israel accuse the Islamic republic of trying to build a nuclear bomb, a charge it denies.
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Several opposition officials in Israel have pleaded with Netanyahu to cancel the speech so as not to undermine the "special relationship" it has with the US.
Speaking Monday, Obama acknowledged "a very real difference" with Netanyahu over ongoing nuclear talks.
But the Israeli leader brushed aside fears of a dispute, saying: "From the day Israel was established to this day, there have been essential differences between Israel and the US, and relations remained sound -- this will be the case this time as well."
Iran is locked in negotiations with the P5+1 powers -- Britain, China, France, Russia and the United States, plus Germany -- aimed at a deal to resolve a long-running dispute over its nuclear programme.
Under an interim deal, Iran's stock of fissile material has been diluted from 20 percent enriched uranium to five percent in exchange for limited sanctions relief.
But scepticism is mounting about whether a permanent agreement is possible, after two deadlines for a comprehensive accord were missed.