Australian police said Monday they are willing to help Spanish investigators probing sexual assault allegations levelled against Spain's outgoing football supremo Luis Rubiales. 

Rubiales was widely condemned after footage emerged showing him kissing Spanish player Jenni Hermoso on the lips following the team's victory in the Women's World Cup final in Sydney last month. 

Spanish public prosecutors launched a lawsuit against the Spanish football federation president after Hermoso, 33, filed a complaint at the country's National Court last week.

Rubiales, 46, has insisted the kiss was consensual.

The police force for New South Wales, which includes Sydney, told AFP on Monday they would work with Spanish investigators if asked. 

"A report has not been referred to NSW Police. However, if received, officers will liaise with international authorities and assist where required."

Rubiales said Sunday he was stepping down from his post, bowing to weeks of intense pressure in Spain and beyond.

He told television show Piers Morgan Uncensored: "(Family and friends) say to me, 'Luis, you need to focus on your dignity and continue your life. If not, you are going to damage people you love and the sport you love.'"

Rubiales also said he was resigning as a vice-president of UEFA, writing in a letter to European football's governing body: "It is evident that I will not be able to return to my position."