Spain's leftist government on Tuesday escalated a spat with the conservative opposition over its plans to commemorate 50 years since the death of longtime dictator Francisco Franco.

The general's legacy remains a sensitive topic after he overthrew a democratic republic in a brutal civil war and ruled with an iron fist from 1939 until his death in 1975.

Socialist Prime Minister Pedro Sanchez has announced around 100 events in 2025 to mark the half-century since the start of the European country's transition to democracy.

The conservative opposition Popular Party (PP), born in 1989 as the successor to a formation founded by a former Franco minister, slammed the government on Monday for attempting to stoke division among Spaniards.

"They can dig up Franco 100 times and can act as nostalgic for the confrontation between Spaniards. But that will not stop the rest who want to build a future together," PP leader Alberto Nunez Feijoo said.

"They, with their bitterness, let them return to the 40s, 50s, 60s and 70s. What a bore!"

Government minister and spokeswoman Pilar Alegria hit back on Tuesday, saying it was "concerning to say the least" that the PP felt it tiresome to celebrate "50 years of democracy and freedom".

Feijoo also felt "discomfort" because "we all know the history of where the PP comes from", Alegria added.

Next year's commemorations are important to explain that the 1936-1939 civil war "was not just a fight between grandparents", she said.

The successive left-wing governments Sanchez has led since 2018 have tried to revive the memory of the dictatorship's victims at the risk of angering sections of society.

Franco's body was in 2019 exhumed from the grandiose Valley of the Fallen memorial near Madrid -- widely seen as a triumphalist monument to the dictatorship -- and passed a "democratic memory" law in 2022.

The right has vowed to repeal the law, which aims to tackle the legacy of the civil war and honour victims of violence and persecution under Franco, if it returns to power.