Tanzanian Minister for Home Affairs Kangi Lugola said on Saturday police have arrested 20 people in connection with the abduction of the nation's young billionaire Mohammed Dewji.

"Police are still questioning the 20 suspects as investigations continue," Lugola told a news conference in the capital Dar es Salaam.

Dewji, 43, was kidnapped on Thursday at about 5:30 a.m. as he was about to enter a hotel gym for his routine workout in the Oysterbay area in Dar es Salaam.

Lugola said there was still no clue or information about the whereabouts of the young billionaire.

He added the motive for Dewji's abduction was yet to be established as the abductors were still at large.

"Once we pin them down we will be in a position to know their motive for the kidnap," said the minister.

Lugola said police have teamed up with other security organs in the hunt for the abductors, adding "the police will never rest until the culprits are brought to book."

"The public need not worry because the country is very safe. These small incidents happening in some parts of the country should not taint the country's security and image," said the minister.

However, he said, there had been 57 reported cases of abduction of individuals since 2016 where at least 44 were rescued alive.

Lugola said the high rate of abductions was a result of politics and economic hardship where kidnappers claimed ransom, witchcraft beliefs, and sometimes resulted from love affairs gone sour.

Mohammed Dewji is the chief executive and leading shareholder of the MeTL Group, a Tanzanian conglomerate with operations in manufacturing, agriculture, haulage, trading and real estate.

It is one of the largest industrial conglomerates in east Africa, with annual revenues of 1.5 billion US dollars and a workforce of more than 20,000 people.

(Top image: Tanzanian businessman Mohammed Dewji at his office in Dar es Salaam, April 23, 2015. /VCG Photo)