Local television program "Hablemos Claro" reported that when police arrived to Garcia's residence to arrest him, the ex-president shut himself in his room and attempted to take his life.
The former President of Peru has shot himself in the head just moments before police barged down his front door to arrest him.
The ex-premier's lawyer, Erasmo Reyna, has confirmed the shooting and described his client's condition as "delicate".
The 69-year-old Garcia was undergoing emergency surgery for "a bullet wound to his head" at the Casimiro Ulloa Emergency Hospital in Lima, the hospital said.
Garcia, who served as president from 1985 to 1990 and from 2006 to 2011, is under investigation for bribery in connection with a massive corruption scandal that has engulfed a number of former Latin American leaders.
Garcia was under investigation in connection with Brazilian construction company Odebrecht, which triggered Latin America's biggest graft scandal when it admitted publicly in 2016 that it won lucrative contracts in the region with bribes.
It broadcast images of Garcia's son and supporters arriving at the hospital.
He had denied ever receiving money from Odebrecht, which is at the centre of Latin America's biggest corruption scandal after admitting in a 2016 plea agreement with the US Justice Department that it paid corrupt officials across Latin America almost 800 million US dollars (£613 million) in exchange for major infrastructure contracts.
Last year, Mr Garcia asked Uruguay for political asylum after he was banned from leaving the country to keep him from fleeing or obstructing the investigation.
Neighbouring South American nation Uruguay rejected his asylum plea late past year.
During his first term in office, Garcia made history by becoming the country's youngest president at the time as he sat on the most coveted seat aged only 36.
Odebrecht took responsibility for bribes paid in relation to several contracts, including the construction of Lima's Metro while Garcia was in office. Ollanta Humala spent nine months in pre-trial detention in 2017-2018 and Pedro Pablo Kuczynski was arrested without charges last week.