A rugby league Facebook page has published a short snippet of footage alleged to be Napa apparently engaged in a sex act on top of a woman whose face is unseen.

The footage is censored by large emojis covering the genital areas of both.

The man can be repeatedly heard telling the woman to call him Big Papa in the footage which lasts only a few seconds.

She mumbles incoherently in reply before the camera filming the act appears to be dropped or is switched off.

The man resembling Napa looks straight at the camera at one point, but it's not clear whether the woman realises she is being filmed.

There's no indication of who shot the video or subsequently leaked it.

Today the Bulldogs issued a statement acknowledging the existence of the footage but said it was several years old.

Cook Islander Napa, 25, only joined the Bulldogs for the start of this coming season after six seasons with city rivals Sydney Roosters.

A club statement added: "The club has today been made aware of alleged images surfacing on social media of a current player taken several years ago.

"The club has informed the NRL Integrity Unit of the matter. The club is not in a position to comment further at this time."