Prosecutors at Spain's top criminal court said Monday they had opened a preliminary investigation into Luis Rubiales' forcible kiss on the lips of World Cup player Jenni Hermoso on grounds it could constitute a crime of "sexual assault".

"Prosecutors from the National Court have opened a preliminary investigation to look into the facts, which could constitute an offence of sexual assault," a court statement said.

They would also contact Hermoso to offer her a chance to file a suit within 15 days, the statement said.

After Spain won the Women's World Cup in Sydney on August 20, Rubiales sparked a massive backlash after forcibly kissing Hermoso on the lips during the medal ceremony.

Hermoso later said the unwanted kiss had left her feeling "vulnerable and a liked the victim of an assault", with a statement on social media describing it as "an impulsive, macho act, out of place and with no type of consent on my part".

The court said it was opening the investigation in light of the "unequivocal nature" of her statements, saying it was necessary "to determine their legal significance".

"Given the public statements made by Jennifer Hermoso, the sexual act she was subjected to by (Luis) Rubiales was not consensual," the court statement said.

Legal experts would also contact the player "to offer her the option of legal action, giving her the chance to contact National Court prosecutors within 15 days for information about her rights as a victim of an alleged sexual assault... should she wish to file a complaint", it said.

FIFA suspended Rubiales as president of Spain's RFEF football federation at the weekend, and he could face further sanctions in Spain with the country's National Sports Council (CSD) meeting on Monday to discuss to examine the complaints against him.