Former US Vice-President Al Gore will not face assault charges due to lack of evidence, law enforcement officials say.

The authorities say there is "a lack of credible evidence" over allegations that he groped and assaulted a masseuse in his hotel room in Portland, Oregon, in 2006 and they also said that the claims do not warrant a criminal prosecution.

The decision comes a month after police reopened the investigation, reports the BBC.

Gore does not dispute that he had a massage from Molly Hagerty, 54, but denies any assault took place.

The case, which was closed previously because of a lack of evidence, was reopened in June after Haggerty told the National Enquirer magazine that Gore had tried to assault her.

Having reopened the case, prosecutors reportedly chose not to pursue it because Hagerty had refused a polygraph test and appeared to have been paid by the magazine.

Gore was in Portland to deliver a speech on climate change when the massage in question took place. (ANI)