Messi and his father, Jorge, have been charged with three counts of tax fraud worth $6.1million during a period from 2007 to 2009.

The Barcelona forward's lawyer Enrique Bacigalupo was present when proceedings began on Wednesday (AEST), but the 28 year-old arrived to testify personally on Friday (AEST).

Messi was met with a mixed reaction during his walk up the courthouse steps, but one voice from the crowd jeered: "P*** off and play in Panama, b*****d!"

While in court, the Argentina captain denied any knowledge of tax fraud, insisting football is his primary focus.

Messi is due to represent Argentina in the first match of its Copa America Centenario campaign against 2015 winner Chile in California on Tuesday (AEST).