Tanzanian police on Tuesday intercepted and impounded 30 trucks loaded with tonnes of maize destined for neighbouring Kenya.
Hamisi Issah, the Kilimanjaro Regional Police Commander, said they had also arrested the truck drivers and believe there is a syndicate exporting Tanzanian maize.
The seizure of the maize-loaded trucks came barely a day after Tanzanian Prime Minister Kassim Majaliwa banned exports of unprocessed food crops.
Majaliwa was speaking at this year's Idd-ul-Fitr celebration, in Moshi Municipality in northern Tanzania's region of Kilimanjaro. He said the ban is meant to encourage investment in agro-processing industries.
The regional police chief said that some of the trucks were intercepted near Tarakea and Holili border posts.
"This follows an operation carried out since Monday night and early Tuesday. The operation involves special team made by police and other security agencies," he said
On Monday night they impounded eight trucks, he said, while other trucks were found while hidden in people's farms on Tuesday morning.
He said some of the trucks were found in a small town of Himo in Moshi rural district in Kilimanjaro.
"Some of the trucks were found when the traders were trying to transfer the maize bags to the mini-trucks so that it can be easy for them to smuggle the maize," he said.
Mr Issah said the two border posts of Tarakea and Holili are under tight security to ensure that Majaliwa's order is observed.
"We're also investigating government officials such as police, customs officials in those border posts who are being involved in facilitating the smuggling of maize to the neighbouring countries," he said.
The official said that some officials at the border posts were suspected of facilitating the smuggling of unprocessed food crops.
So far, Tanzania has received requests from Somalia, Ethiopia, South Sudan and the Democratic Republic of the Congo (DRC) to provide relief food.