Neymar appears before a judge regarding allegations into his transfer to Barcelona

Brazil international Neymar has appeared before a judge to testify regarding alleged irregularities over his transfer to Barcelona.

The Barca striker's father, Neymar da Silva Santos, who acts as his agent, is also due to be questioned by judge Jose de la Mata at the National Court in Madrid.

Current Barcelona president Josep Bartomeu and predecessor Sandro Rosell have already denied any wrongdoing when they testified on Monday.

The court is looking into a complaint made by a Brazilian investment group, which claims it was financially harmed when Barcelona and Neymar allegedly withheld the real amount of the player's transfer fee from Santos in 2013.

Investment group DIS was entitled to 40 per cent of Neymar's transfer from Santos, but claims it received a smaller compensation than it should have because part of the transfer fee was concealed.

Representatives of Santos were also in court on Monday and claimed the club was deceived by Barcelona and Neymar.

But Barcelona delegates told the judge that all legal protocols and regulations were met in Neymar's transfer.

Rosell resigned in 2014 following the allegations involving the transfer of the 23-year-old.

Barcelona maintain the deal cost the club 57.1m euros. Santos officially received a payment of 17.1m euros, with the remaining 40m euros going to a company owned by Neymar's father.

But investigations in Spain later showed that Barcelona spent nearly 83.3m euros to acquire the Brazilian.

Neymar has also been facing problems with Brazil's tax office, which last year froze assets related to the player because of allegations of tax evasion. He has denied any wrongdoing in Brazil and Spain