Minister tells Parliament that the country was still in consultation with Kenya over plans to halt the construction of the proposed dams.
He said discussions started immediately after Tanzania learnt that Kenya was planning to build the dam in 2016.
The river is considered the lifeline of millions of wild animals in the Serengeti ecosystem and the multi-million tourism industry in both countries.
Tanzania on Monday said that it was negotiating with Kenya to stop the planned construction of hydroelectric dams on River Mara and its tributaries.
The announcement follows reports that Kenya would construct the dams on the 400-kilometre long river.
The planned dams are Norera (10 metres high) and Mungango (30 metres). The Mara is formed after the confluence of the Amala and Nyangores Rivers.
The river, with a drainage area covering 13,504 square kilometres, is considered the lifeline of millions of wild animals in the Serengeti ecosystem and the multi-million tourism industry in both countries.
River Mara originates from the Mau Forest in Kenya's Rift Valley and empties into Lake Victoria.
It lies across the path of the world-famous wildebeest migration.
Kenya’s acting director of trans-boundary waters at the ministry of water, Gladys Wekesa, in November 2017 said that no construction had started.
The EAC Treaty, which Tanzania and Kenya are signatories, calls for the promotion of sustainable utilisation of the natural resources of the partner states and taking measures that would effectively protect the natural environment.
Tanzania's deputy minister for Natural Resources and Tourism, Constantine Kanyasu, told Parliament Monday that the country was still in consultation with Kenya over plans to halt the construction of the proposed dams.
“The dams will lead to an adverse impact on the Serengeti ecosystem, including the loss of some species due to lack of water in the Mara River during the dry season,” said Kanyasu.
Responding to a question in parliament, Mr Kanyasu said negotiations for stopping the implementation of the planned dams were being coordinated by the Lake Victoria Basin Commission (LVBC) under the ministry of Foreign Affairs and East African Cooperation.
He said discussions started immediately after Tanzania learnt that Kenya was planning to build the dam in 2016.
This is not the first time that Tanzania and Kenya find themselves scrambling for a shared resource, mostly due to climate change outcomes and foreign exchange from tourism.
