The coastal region was hit hardest, with 126,831 people affected, according to the government.
Government spokesperson Mobhare Matinyi said on Sunday that essential supplies including food had been distributed to those affected.
Tanzania plans to construct 14 dams to prevent flooding in future, he added.
East Africa is experiencing heavy rains, with reported flooding in neighboring Kenya killing at least 13 people so far.
Infrastructure has also been damaged and those living in flood-prone areas are being urged to move.
The rains are expected to reach their peak towards the end of this month.
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