Former Philippine president Fidel Ramos, a soldier regarded as one of the country's most effective leaders ever, was interred at the National Heroes Cemetery on Tuesday in a sombre state burial.

A low-flying military helicopter dropped flowers as a wagon bearing the flag-draped coffin containing an urn with his ashes rolled through the leafy cemetery grounds, lined with white crosses marking the tombs of dead soldiers also buried at the site.

Incumbent President Ferdinand Marcos Jr joined the ex-leader's widow and relatives as the silver urn with the cremated remains was lowered into the ground after a military parade and a 21-gun salute.

A career soldier who oversaw a rare period of steady growth and peace in the turbulent years that followed the dictatorship of Marcos Jr's father and namesake, Ramos died late last month aged 94. The cause of death was not specified.

Known as "Steady Eddie" for his unflappable demeanour during the country's regular moments of upheaval, he was frequently pictured chewing unlit cigars as he guided the Philippines with a sure hand from 1992-1998.

His widow Amelita Ramos thanked Filipinos in a brief address at the end of the state burial, saying soldiers like him lived a "hard life".

"It entailed difficult adjustments. He would be at home for two years and in the province two years after that," she said, apart from overseas deployments in the Korean War and the Vietnam War.

A graduate of the prestigious West Point military academy in the United States, Ramos also saw combat against communist guerrillas back at home.

He was later commander of the paramilitary Philippine Constabulary -- the key institution that enforced the brutal repression of dissent after Marcos Sr declared martial law in 1972.

Ramos broke from Marcos Sr in February 1986, throwing his support behind a group of young military officers who holed up in a Manila military camp after their plot to topple the leader in a coup was discovered.

Coming amid popular outrage over the 1983 murder of opposition leader Benigno Aquino and massive regime cheating in a snap election, the events led to a peaceful "People Power" revolt that sent the dictator into exile.

An endorsement from Corazon Aquino, the assassinated politician's widow and the first post-Marcos president, helped Ramos score a narrow presidential victory in 1992.

As president, he solved a crippling power crisis caused by years of under-investment in energy, and broke up cartels in telecommunications, aviation and shipping -- boosting a moribund economy that reaped a period of renewed growth.

He also signed peace deals with Muslim separatists and military coup-plotters, but communist guerrillas rejected his overtures.

Ramos was also a key, early supporter of Rodrigo Duterte, who won the presidency in 2016.

The relationship swiftly soured as Ramos criticised Duterte's expletive-laden speeches, his moves away from the US alliance and his anti-drug campaign that claimed thousands of lives.

The last former president to be buried at the National Heroes Cemetery was Marcos Sr in 2016, courtesy of Duterte who brushed off popular outrage at his plan.

Marcos Jr won a landslide election victory last May, completing the rehabilitation of the family name.