Panamanian prosecutors demanded a 21-year sentence for spying against ex-President Ricardo Martinelli during an indictment hearing in the capital Panama City.
Martinelli, who was extradited back to Panama last month from self-imposed exile in the United States, is accused of "giving orders" to his Security Council to "illicitly intercept many citizens' communications" between 2012 and 2014.
The 66-year-old was detained a year ago in Miami after an international arrest warrant was issued against him. Panama accused him of graft and spying on his political foes, and submitted an extradition request to the US.
He is accused of intercepting emails, telephone calls, memory cards, phone books and audio recordings of confidential conversations.
Prosecutor Henry Diaz, who on Monday read out 30 pages of accusations, said Martinelli conducted "political espionage" without judicial authority against opponents, union leaders and civil society groups that constituted "a continued and systematic violation of intimacy and human rights."
President from 2009 to 2014, supermarket tycoon Martinelli fled to the US in 2015 to avoid arrest. He denies the accusations, claiming they are politically motivated.
He is also accused of helping to embezzle $45 million from a government school lunch program as well as other cases of extortion, bribe-taking, misappropriation of public funds and abuse of power.
Ricardo Martinelli is accused of graft and spying on his political foes but he has many supporters in Panama