Chairwoman of the Senate Appropriations Committee Senator Barbara Mikulski said the Democrats wanted the budget in an emergency funding bill on Tuesday, Reuters reported.
"Israel is an essential American ally and needs these assets to defend itself," the Maryland Democratic senator said in a statement.
Israel said its Iron Dome system has intercepted about a fifth of more than 2,000 rockets the Palestinians have fired during the current conflict.
The fate of the proposed budget is uncertain in the GOP-controlled House of Representatives, where there is stiff opposition to an increase in spending tied to President Barack Obama's request.
Meanwhile, the bloodshed continues in the Gaza Strip for the16th straight day as there is no let-up to the Israeli onslaught on the enclave.
According to Palestinian medics, more than 15 people have been killed so far on Wednesday.
A total of 647 Palestinians have died and more than 4,000 others injured since Tel Aviv unleashed its offensive.
Tanks and artillery continue shelling northern and eastern Gaza, while warplanes keep pounding the region.
Palestinian resistance fighters have also retaliated against the deadly Israeli attacks by firing a barrage of rockets deep into the Israeli-occupied Palestinian territories.
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