The midfielder, who also plays for Real Madrid, is suspected of making false statements at the tax fraud trial of Zdravko Mamic, his former manager.
Mr Mamic, a powerful figure in Croatian football, was Mr Modric’s boss at leading club Dinamo Zagreb.
Mr Mamic, his brother Zoran Mamic, and two others are accused of corruption that reportedly cost Dinamo Zagreb more than 15m euros (£13.1m; $16.7m), and the state 1.5m euros.
Cash is said to have been embezzled via phoney deals where they took a cut from the sales of players.
If found guilty of perjury, Mr Modric could face between six months and five years in prison.
Mr Modric was asked to testify about his multi-million pound transfer from Dinamo the English club Tottenham Hotspur in 2008.