Keiko Fujimori, the daughter of the former Peruvian President Alberto Fujimori, has been arrested as part of an investigation into money laundering, BBC reports.
Mrs Fujimori, who is leader of the opposition in the Peruvian congress, was detained along with her husband.
The judge said they would be held initially for 1days along with 19 other suspects.
Prosecutors allege she was involved in accepting illegal contributions to her party by the Brazilian firm, Odebrecht.
Mrs Fujimori denies any wrong-doing.
She was shown on television on Wednesday in a car in handcuffs after being detained.
Prosecutors have accused her of leading a criminal group inside her party that took $1.2m (£920,000) in illegal funds from Odebrecht for use during her 2011 presidential election campaign.