MADRID: Neymar is expected to appear before a judge in Madrid to testify in an investigation into alleged irregularities regarding his transfer to Barcelona.

Neymar's father, who acts as his agent, is also scheduled to testify at the National Court on Tuesday.

Barcelona's current and former club presidents denied any wrongdoing when questioned by the same judge 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 Brazilian club 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.