Mbowe declared September 1 this year a day of "defiance" and urged supporters of Tanzania's main opposition party to stage demonstrations across the country to protest against what he described as a blanket police ban on political activities.
The Tanzania Police Force last month banned all political rallies and demonstrations indefinitely, saying it had received intelligence reports suggesting that the opposition planned to use the rallies to call for the launch of a campaign of civil disorder in the country.
But Mbowe said yesterday that CHADEMA's central committee has now ordered the party to stage nationwide public rallies and protests to defy the "undemocratic and unconstitutional" police ban.
"Since public rallies and political activities are our democratic right ... CHADEMA is hereby declaring Sept. 1 this year a day for public rallies, including demonstrations, across the country," he told journalists yesterday in Dar es Salaam.
"We will hold these public rallies in defiance of the order issued by the president and police."
CHADEMA and other opposition parties under the UKAWA coalition group last month called for nationwide rallies to protest against the government's decision to ban live televised parliamentary debates.
Police swiftly outlawed the planned demonstrations for security reasons and has since maintained on several occasions that the ban was still in force.
Mbowe said yesterday that CHADEMA would follow procedure, which requires the party to officially inform the police about its planned public rallies and demonstrations, but warned authorities against interfering in the process.
Magufuli last month told opposition parties not to stand in his way by trying to derail implementation of his 2015 election promises through destructive politics.
The president urged opposition parties to conduct their activities in formal political bodies such as Parliament instead of staging public demonstrations.
Magufuli has since come under scathing attack from opposition leaders who have accused him of banning political activities in the country.
Some opposition party leaders claim that Magufuli is showing "dictatorial tendencies", but the president has publicly rebuffed them by saying "I am not a dictator."
The commissioner of police for training and operations, Nsato Marijani, was non-committal yesterday when asked by The Guardian if police would allow the planned Sept. 1 opposition protests to take place across the country.
“We will carefully analyse the country’s security and political situation to see if the proposed demonstrations and public rallies would result in civil disobedience or not," he said.
"If we are satisfied that the demonstrations will be peaceful, then we will let them go ahead."
The spokesman of the ruling Chama Cha Mapinduzi (CCM) party, Christopher ole Sendeka, could not immediately comment yesterday on the move by the opposition party.
“I'll need some time to go through what they (CHADEMA) are planning to do then I will have something to say," he remarked.
The police ban on political meetings and rallies has sparked criticism from activists and democracy crusaders who describe it as unconstitutional.
The United States ambassador to Tanzania, Mark Childress, has also expressed concern over the government's decision to ban political meetings. In a message to Tanzanians on July 4, he said:
"I am mindful when Tanzanian voices raise concerns about the closing of democratic space, whether that be the banning of political rallies or restrictions to televising the sessions of Parliament. I believe the fight against corruption – an admirable goal of great importance to both our nations – need not be waged at the peril of debate, dissent, or free speech."
"In fact, it is this very creative tension between competing ideas that makes democracies stable, prosperous, and representative of the people."
The United States, which is Tanzania's largest bilateral development partner, in March cancelled aid worth over 1 trillion/- to the country under the Millennium Challenge Compact (MCC) programme due to concerns about the conduct of the Zanzibar election rerun and enforcement of the Cybercrimes Act.