PRISTINA, Yugoslavia (AP) _ At least 29 people have died and 127 have been injured in ethnic riots in a southern province, and some victims bled to death because fierce fighting prevented them from reaching hospitals, news reports said today.

The death toll reported by the Belgrade daily Vecernje Novosti was four higher than that given by officials. An unofficial emigre group put the death count at 137.

An official newspaper suggested the higher numbers were aimed at fomenting more unrest in the province of Kosovo.

Marija Gasi, a spokeswoman for Kosovo's government information office, told reporters today 23 people had died and 92 demonstrators and 121 policemen had been injured.

Vecernje Novosti cited ''the latest available information'' for the report from Pristina, the provincial capital. Reliable sources in Pristina said they had heard the same death toll from police.

Vecernje Novosti said two policemen and 27 demonstrators died in clashes Monday and Tuesday between security forces and ethnic Albanians. It said 97 demonstrators and 30 policemen were injured in the bloodshed, which was sparked by a decision to give the republic of Serbia more control over Kosovo, its autonomous province.

Serbs contend the constitutional changes, which took effect Tuesday, are needed to protect Kosovo's mainly Christian Slav minority from the mainly Moslem ethnic Albanians, who make up 85 percent of the 1.9 million population.

Ethnic Albanians say the changes threaten autonomy won under Yugoslavia's 1974 constitution.

Vecernje Novosti said seven Kosovo settlements dominated by the province's Slav minority had set up patrols and posted guards around the settlements.

Another Belgrade daily, Borba, said a policeman who died in Titova Mitrovica on Monday after being shot did not die immediately but bled to death because intense rioting delayed his transfer to a hospital.

Other media accounts said another wounded police officer had to wait an hour before getting to a hospital because of the fighting and died shortly afterward.

Borba, a Communist Party daily, indicated some of the worst violence occurred in the village of Zur, near the border with Albania. It said protesters there used ''bombs'' in the clashes. Some of the bombs exploded prematurely and injured several demonstrators, it said.

Borba also said five policemen caught between demonstrators in the village of Dusanovo had to be rescued by helicopters.

The entire province was under a nighttime curfew.

The Slovene Communist party daily Delo took the unusual step of publishing on its front page today what it said were casualty figures from an emigre Albanian group in Brussels. Those figures listed 137 dead and 370 injured.

Yugoslav authorities have said ethnic Albanian emigre groups foment unrest in Kosovo and exaggerate casualty figures.

Police refused comment on the reports of higher death tolls, and Borba suggested the numbers were intended to instigate further unrest.

''The enemy is trying everything to incite the revolt of the ethnic Albanian population,'' it said. ''To this end, they are using in particular disinformation about the number of killed demonstrators.''