President Donald Trump's top economic advisor, Larry Kudlow, said Tuesday that the White House is "talking to a number of candidates" to fill two open seats on the Federal Reserve Board of Governors, while insisting that controversial Trump picks Herman Cain and Stephen Moore are still in the running.

Asked Tuesday whether the White House was interviewing anyone else for the two Fed seats in case Cain and Moore drop out, Kudlow said: "We're talking to a number of candidates. We always do."

The potential nominations of Cain and Moore, which would need confirmation in the Senate, have been met with lukewarm reactions from economics experts and some Republicans. Both men have faced controversies – a messy divorce in Moore's case, and allegations of sexual misconduct in Cain's. Cain has denied the accusations.

Critics also say the two men are too politically biased toward Trump to serve on the independent Fed board.

Cain in particular has faced resistance from GOP senators, four of whom have already said they would vote against him to join the central bank's seven-member board of governors.

North Dakota Republican Sen. Kevin Cramer's announcement of opposition to Cain last Thursday effectively doomed his nomination, assuming Democrats in the chamber would vote against him.

GOP Sens. Lisa Murkowski of Alaska, Cory Gardner of Colorado and Utah's Mitt Romney have also said they would vote against Cain.

"Herman's going through the vetting process, for now, that's where we are on that," Kudlow said of the former presidential candidate and ex-CEO of the Godfather's Pizza restaurant chain. Cain had previously served at the Kansas City Fed before moving into politics.

"At the end of the day, it'll probably be up to Herman Cain if he wants to stay in that process or not. As far as we're concerned he's in that process. And it's proceeding in an orderly way," Kudlow told reporters at the White House.

Kudlow, director of the White House National Economic Council, pushed back when pressed by reporters whether that tepid endorsement was meant as a hint for either Cain or conservative think tank fellow Moore to get out of the running for the Fed seats.

"Stephen Moore is in the process. We support him. We support Herman Cain. We'll just let things play out in the vetting process," Kudlow said.

The White House did not immediately respond to CNBC's request for comment on Kudlow's remarks.