LILONGWE (Reuters) - Malawi has protested against plans by its neighbor Tanzania to deploy two ships on Lake Malawi, which it says threaten mediation efforts to resolve a long-standing border dispute.

Malawi's Foreign Affairs Minister Ephraim Chiume said on Saturday that Tanzanian government officials had stated publicly that the East African nation was buying six new passenger ships, two of which were destined for Lake Malawi.

"The Malawi government found these developments unfortunate, especially coming at a time when the mediation process over the boundary dispute is going smoothly," Chiume said.

Tanzanian officials were not immediately available to comment.

Malawi, which sits to the west of Africa's third-largest lake, claims the entire northern half of the lake, while Tanzania, to the east, says it owns half of the northern area. The southern half is shared between Malawi and Mozambique.

Last month Malawi returned to talks aimed at resolving a dispute over Lake Malawi that has soured relations between the two countries and delayed exploration for oil and gas.

It had pulled out of the dialogue in October, accusing its neighbor of intimidating Malawi fishermen, a charge Tanzania denied.

A year ago, impoverished Malawi awarded oil exploration licenses to British-based Surestream Petroleum to search for oil in Lake Malawi, which is known as Lake Nyasa in Tanzania.

(Reporting by Mabvuto Banda; Editing by George Obulutsa and Alistair Lyon)