Former US vice-president Joe Biden said on Sunday he believed he had never acted inappropriately following allegations by a female activist that he made her feel uncomfortable by kissing her at a campaign event in 2014.

"In my many years on the campaign trail and in public life, I have offered countless handshakes, hugs, expressions of affection, support and comfort. 

"And not once - never - did I believe I acted inappropriately. If it is suggested I did so, I will listen respectfully. But it was never my intention," Biden said.

Biden said he does not recall the 2014 incident.

The allegation was made in an online essay published on Friday by Lucy Flores, a party activist who was running to be Nevada’s lieutenant governor. 

Flores said Biden also touched her shoulders and smelled her hair when they appeared at an event together, making her feel uncomfortable.

"I may not recall these moments the same way, and I may be surprised at what I hear. But we have arrived at an important time when women feel they can and should relate their experiences, and men should pay attention. And I will," Biden's statement continued.

Biden served eight years as vice president under former president Barack Obama and 36 years in the US Senate. He has not yet said whether he will run for president in 2020, but has been expected to throw his hat into the ring soon.

- Reuters