Jeb Bush says President Donald Trump did not obstruct justice when he fired former FBI Director James Comey.

"But who cares what I think?" Bush said during a speech at Boston College on Thursday, according to the Boston Herald.

Bush, the former governor of Florida who ran against Trump for the Republican presidential nomination in 2016, said he wished the president would focus on work.

"It would be great to get back to the business of governing and less about the swirling controversies. I just think the president needs to focus on doing his job," Bush said.

"The judicial appointments have been good, he's got a great foreign policy team, he should be president and stop creating all the controversies — let that process take its place."

However, the former governor noted that he did not vote for Trump, but had high hopes for the president's campaign plan to "drain the swamp" in Washington.

"'Drain the swamp' was a classic line. It resonated with me… I didn't vote for the guy, I'm not a big fan and everybody knows that, but I was hopeful that he would drain the swamp and the swamp-draining would include lobbying reform," Bush said.

At another point during his speech, Bush said he believed the work of Robert Mueller, the special counsel in charge of the Russia probe, was more important than Comey's testimony.

"There is a process underway and the testimony today is not as relevant to me, in that regard, as Mr. Mueller's activity," he said.