India's telecommunication ministry wants to auction additional bandwidth, but many mobile-phone companies, especially those operating GSM networks, say that what is being made available is too little and too expensive.

In her letter to Singh, Ho Ching wrote, "The latest proposals risk making private operators subscale, when they have a real window of opportunity to be global champions.... As a long-term investor in India, it is my sincere suggestion that you invite your regulators to consider the best practices and strategies around the world."

Temasek holds a 56 percent stake in SingTel, which in turn owns about 31 percent of Bharti Airtel, India's largest mobile-phone service provider by subscriber base.

India's defense ministry controls most of the remaining frequencies that could be made available for mobile-phone services and is not willing to release as much bandwidth as the telecommunications ministry wants.

"We would be happy to play our part to help facilitate any exchanges with other regulators," the Temasek C.E.O. wrote. "We also believe that the private sector players are a rich source of market knowledge. An open dialogue with these excellent operators should help develop a consensus which would be advantageous to India's interest."

The directness of her letter was typical of Ho Ching's management style. She joined Temasek as a director in January 2002 and became its executive director in May 2002. On January 1, 2004, she became chief executive, sparking talk of nepotism because her husband was Singapore's prime minister.

Ho Ching—who holds a master's degree in electrical engineering from Stanford University—started her professional career with Singapore's Ministry of Defense, where she held various positions in the Defense Science Organization and the Defense Matériel Organization. She next served in the Singapore Technologies group, where she was chief executive.

Ho Ching has long emphasized that the key reforms in the island-state of 4.5 million people included the opening up of its markets and a determination to maintain fiscal discipline.

At the Morgan Stanley conference last year, she shared some of her thinking: "We look for sectors like infrastructure, transport and logistics, banking services, and financials because these are broad-based reflections of the economic opportunities. A second theme is to focus on services, products, or companies that serve the middle class. This includes consumer banking and telecommunications."

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