Senate Republican Whip John Thune told CNN there is "a lot of resistance" to the nomination of Jack Lew to be the US ambassador to Israel, a sign that Democratic efforts to push for his quick confirmation could hit roadblocks in the chamber.

Lew, who is scheduled to have a confirmation hearing Wednesday, would need the support of all 100 senators to schedule a quick confirmation vote. But if any one member objects it would force Senate Majority Leader Chuck Schumer to take time-consuming procedural steps to overcome the objection.

Thune's comments suggest that there could be a fight over getting Lew confirmed to the post. It would require a simple majority of 51 senators to advance the nomination.

"I think it'll depend a lot on how the process goes, what's the confirmation hearing look like," Thune told CNN. "But as you know we've got a lot of resistance to it over Iran. And I think that's, I think that'll probably play heavily. But I'm sure will be a subject of conversation (Tuesday) at our policy lunch."

Republicans have been criticizing Lew over his role in the Iran nuclear deal during the Obama administration when he served as treasury secretary. Republican Sen. Tom Cotton of Arkansas told Fox News on Sunday that Lew was bad for the United States and Israel.

"We need to defeat Jack Lew's nomination to show we have a new approach to Iran," Cotton said.

Lew's confirmation hearing is before the Senate Foreign Relations Committee on Wednesday.

On Monday, Schumer called for the Senate to quickly confirm Lew.

"I urge the committee to approve Mr. Lew as soon as possible, without any costly partisan delays, so we can bring him to the floor and confirm him with all due haste," Schumer said. "Mr. Lew has proven himself a strong public servant, a ferocious ally of Israel. So delaying him would be egregious at a time like this, we must move him quickly."