Argentina forward Lionel Messi and his father Jorge were ordered on Thursday to appear before a Barcelona court in September after Spanish prosecutors accused the pair of tax fraud.

Earlier in the day, Spanish media reported that an examining magistrate had brought official charges against the Messis but a writ showed the two had been summoned to give evidence.

The magistrate has accepted a complaint from the Catalonia tax crime prosecutor, who has accused Barcelona's World Player of the Year and his father of defrauding the Spanish tax office of more than 4 million euros ($5.4 million).

"The judge has accepted the complaint presented by the prosecutor against Lionel Messi and Jorge Horacio Messi for three alleged crimes against the tax authorities," a statement from the Barcelona court said.

"The acceptance of the case is the next step after a complaint is presented. The court can start to investigate and reach a conclusion as to whether a crime has been committed or not.

"The magistrate has called the accused to give evidence on September 17."