Dewji is also the main shareholder in Tanzania's Simba FC football club.
In 2016, Dewji signed The Giving Pledge in 2016 and promised to donate at least half his fortune to philanthropic causes.
Shots were fired as Mohammed Dewji, 43, was snatched from the Colosseum Hotel and Fitness Club in Dar es Salaam and driven away by a gang of four men at dawn.
He served two terms in the Tanzania parliament before he resigned in 2015 to dedicate more time to the family business. He told the BBC in a 2014 interview that this possibly made it easier for him to meet top politicians, but it did not give him an unfair advantage, as other businessmen also had access to them.
"I've spoken to his father and the news of the kidnap of our friend Mo is true", State Minister for Environment and Union Affairs January Makamba said on Twitter.
Mohammed Dewji has huge celebrity status in Tanzania.
Dewji is Africa's youngest billionaire.
Makonda said police have tightened security at all border points and airports to ensure that the two white men who were seen on surveillance video did not leave the East African nation.
The kidnappers, two of which were described as white men, fired shots into the air before peeling off with Dewji in a vehicle, witnesses said.
Dar es Salaam regional commissioner Paul Makonda was among government officials who arrived at the scene.
"There were two white people involved, we are yet to establish the motives behind abduction", Mr Mambosasa said, adding that investigations are underway.