Mauritius inaugurated on Thursday an Indian-financed air strip and jetty on the island of Agalega, but denied the remote islet would be used for military purposes.
An investigation by news broadcaster Al Jazeera in 2021 said India was building a secret naval base on Agalega, much to the chagrin of its approximately 300 inhabitants.
"There has never been a project to turn Agalega into a military base," Mauritius Prime Minister Pravind Jugnauth said.
"I strongly deplore and condemn the India-bashing campaign fomented by some people in Mauritius and abroad."
The three kilometre (1.9-mile) air strip and jetty were agreed upon during Indian Prime Minister Narendra Modi's 2015 visit to Mauritius and cost 8.8 billion mauritian rupees ($192 million).
Jugnauth said the infrastructures would help the Indian Ocean island modernise and strengthen its security.
"They will strengthen the fight against drugs, human trafficking and illegal, unreported and unregulated fishing, and will enable emergency response," he said.
An archipelago of four islands, Mauritius also includes Saint-Brandon and Rodrigues, which has had an autonomous status since 2001.
The report of a naval base in Agalega raised fears of a repeat of the 1965 decision by Britain to separate the Chagos Islands from Mauritius and set up a joint military base with the United States on Diego Garcia, the largest of the isles.
The decades-old move has sparked protests by Chagossians, who accuse Britain of carrying out an "illegal occupation" and barring them from their homeland.
Britain insists the islands belong to London and has renewed a lease agreement with the United States to use Diego Garcia until 2036.
Diego Garcia's air and sea bases played a strategic role during the Cold War and during the war in Afghanistan.