Rafael Roncagliolo, 68, resigned "strictly because of health reasons," the office of President Ollanta Humala said in a statement.

Justice Minister Eda Rivas will be Peru's new foreign minister, the government said. Daniel Figallo, a deputy minister of human rights, will replace Rivas as justice minister.

"He has done an impeccable job with the foreign relations of our country," the statement said of Roncagliolo.

Roncagliolo, appointed by Humala in 2011, faced increasing criticism from the left and right in recent weeks over his handling of diplomatic tussles.

In early May, Roncagliolo called for "tolerance" in Venezuela and urged the South American bloc Unasur to mediate political tensions in Caracas after a disputed election there won by President Nicolas Maduro.

Maduro complained that Roncagliolo was giving voice to opposition leaders.

"You may be Peru's foreign minister, Roncagliolo, I know you well, but you cannot give your opinion on Venezuela," Maduro said in a televised speech. "I hope that is not the position of President Ollanta Humala."

Maduro said Humala spoke with Venezuela's ambassador to Peru and Lima then softened its tone.

Humala was a friend and admirer of Maduro's political mentor, late Venezuelan President Hugo Chavez.

Peru's ambassador to Venezuela resigned on May 8 after opposition lawmakers in Peru's Congress criticized comments he made in support of Maduro's government.

Earlier this month, Ecuador's President Rafael Correa said Lima acted prematurely by asking Ecuador's ambassador in Peru to leave the country after he was involved in a scuffle with women in a supermarket.

(Reporting By Omar Mariluz; Editing by Terry Wade, David Brunnstrom and Mohammad Zargham)