A deadly stampede at a football match killed at least 56 people in Guinea's second city N'Zerekore, the government said.

The events at Sunday's match, which were initially reported as clashes between fans, were triggered after a player was sent off at the end of the game, witnesses said.

The match in the southeastern city was the final of a tournament organised in honour of Guinea's junta leader, Mamady Doumbouya, who seized power in a 2021 coup and has installed himself as president.

The opposition has accused the junta of using sport for political ends.

Witnesses said fans invaded the pitch following the referee's decision, with some attacking the stand designated for officials, prompting the intervention of security forces.

"Protests of dissatisfaction with refereeing decisions led to stone-throwing by supporters, resulting in fatal stampedes," said a government statement which was read out on national television.

"Hospital services have put the provisional death toll at 56, with several others injured," it added, describing the incident as a "tragic event".

"The government assures the public that investigations will be carried out to establish who is responsible for this unfortunate event," the statement said.

Young people also set fire to a police station overnight, according to public television.

Prime Minister Amadou Oury Bah condemned the "incidents that marred the match between the teams of Labe and N'Zerekore", in a post on Facebook.

"The government is following the situation and reiterates its call for calm so as not to impede hospital services from aiding the injured," he added.

Local media reported that hospital wards and a morgue were overwhelmed by the injured and dead.

Such tournaments and other public gatherings have become common in the West African nation, in what is widely seen as a campaign to promote Doumbouya's candidacy in any future presidential election.

The military seized power by force in September 2021 by overthrowing civilian President Alpha Conde.

Under international pressure, the junta pledged to hand power back to a civilian government by the end of 2024 but has since made clear it will not. (AFP)