Giuliani says time for Russia probe to end

Special counsel Robert Mueller should wrap up his probe into whether there was Russian collusion with Donald Trump's presidential campaign, Rudy Giuliani says.

Donald Trump's lawyer Rudy Giuliani says Robert Mueller should now wrap up his Russian probe. (AAP)

President Donald Trump's lawyer Rudy Giuliani is urging special counsel Robert Mueller's team to wrap up its Russia investigation on the eve of the probe's one-year anniversary.

Giuliani told Fox News Channel's Laura Ingraham on Wednesday that Mueller "has all the facts to make a decision" after 12 months investigating Russian meddling in the election and possible collusion with Trump's campaign.

"Mueller should now bring this to a close," said Giuliani, the former mayor of New York. "It's been a year. He's gotten 1.4 million documents, he's interviewed 28 witnesses. And he has nothing, which is why he wants to bring the president into an interview."

"It's about time to say enough. We've tortured this president enough," he added, describing the investigation as being "like a big weight" on the president's back.

Giuliani's team has been weighing whether to allow Trump to sit for an interview with Mueller. He told Ingraham he's been asking what Mueller expects to learn from Trump in an interview that he doesn't know already.

So far, the special counsel's office has charged 19 people - including four Trump campaign advisers - and three Russian companies. Trump's former national security adviser, Michael Flynn, and his deputy campaign chairman, Rick Gates, have pleaded guilty and are now cooperating with the probe.

Trump, however, has panned it as a "witch hunt" intended to discredit his presidency and insisted that Russia had nothing to do with his winning 2016 campaign.

Giuliani, who is working for the president pro bono, said on Wednesday that the probe "is not good for the American people, and the special counsel's office doesn't seem to have that sort of understanding that they're interfering with things that are much bigger than them."

He also said all campaigns look for dirt on their opponents, regardless of the source.

"And even if it comes from a Russian, or a German, or an American, it doesn't matter. And they never used it, is the main thing. They never used it. They rejected it. If there was collusion with the Russians, they would have used it," he said.