Peruvian President Pedro Castillo accepted the resignation of his prime minister Wednesday and replaced him with a female environmental activist.

Under Peruvian law, the prime minister's resignation automatically triggered that of the entire cabinet.

Hours later, Castillo swore in environmental and human rights activist Mirtha Vasquez, 46, as his new prime minister in a move seen as a sop to the moderate wing of the informal leftist coalition that supports him. 

Castillo gave no reasons for replacing Guido Bellido as premier, who was a more hardline leftist. Bellido's resignation letter said he was acting at Castillo's "request."

The leftist president, who used to be a rural school teacher, called for "unity" from Peru's economic, political and social sectors to "achieve common objectives" such as reactivating the economy.

Castillo's July appointment of electronic engineer Bellido, a political novice, was controversial from the start.

Peruvian media reported that Bellido, 41, was investigated by prosecutors for allegedly defending terrorism with statements made shortly after taking up his seat in parliament in June.

In comments to the Inka Vision online news outlet, he appeared to defend people who supported the Shining Path Maoist guerrilla group that fought the state from 1980 to 2000 and is designated a terrorist organization by Lima.

In August, Castillo seemed to have staved off a political crisis when the right-wing dominated congress approved his cabinet following a bitter debate.

Until then, Peru had been in a state of political uncertainty since the beginning of the year, when the electoral campaign got under way.

Peru has suffered years of political upheaval and a series of corruption scandals saw three different presidents in office in a single week last November.

Seven of the country's previous 10 leaders have either been convicted or are under investigation for graft.

And Castillo's victory over right-wing populist Keiko Fujimori in June's second round presidential run-off took six weeks to be confirmed after delays in validating the results.