The traditional ruler, who ascended the throne in 2003, was 77.
A palace source hinted that the monarch had earlier attended a security summit held in the town on Tuesday and developed complications after he had retired to the palace and eventually died.
Although the state government was yet to make any official statement on the death of the traditional ruler, the news of his death has spread across the state and beyond.
The Commissioner for Information,Yemi Olowolabi said he was not aware of the development, stressing only Olowo’s palace could confirm the story.
Governor Oluwarotimi Akeredolu, who hails from Owo, is currently on an official engagement outside the country.
However, an official of Owo Local Government Area of the state who spoke in confidence confirmed the death of the monarch.
He stated the chairman of the Local Government will announce his death officially on Thursday.
He said the monarch had been on and off the hospital for over a year, attributing his death to health challenges he suffered since his ascension to the throne.
The late traditional ruler was a prominent lawyer and a law teacher, who produced many prominent lawyers across the country during his lifetime.
He was honoured with the national award of the Commander of the Federal Republic (CFR).
Besides, he was appointed the Chancellor, the University of Benin in 2015 and later the University of Abuja.
The late Oba Olagbegi was a former chairman, Ondo State Council of Obas.