ATHENS (AFP) - Brazil president Dilma Rousseff has cancelled her visit to Greece to witness the lighting of the Olympic flame, the symbolic start of this year's Rio Games, as she battles impeachment at home.

"We knew that Mrs Rousseff was to come, but the Brazilian ambassador informed us today that she would not be coming for the ceremony," Greek Olympic Committee spokesman Tassos Papachristou told AFP.

The lighting of the flame, at Ancient Olympia in the south of the country, is set for April 21 before being handed over to representatives of the Rio Olympics in Athens on April 27.

Rousseff is accused of breaking the law by juggling government accounts to disguise the depth of budget shortfalls during her 2014 reelection.

However, she argues that this relatively technical accusation does not amount to an impeachable offence.