Kathmandu, Aug 10 - Nepal's Foreign Minister Sujata Koirala Monday left for New Delhi for a five-day goodwill visit at the invitation of Indian External Affairs Minister S.M. Krishna, saying it would add a new dimension to India-Nepal ties and resolve misunderstandings.

Koirala, the daughter of five-time former Nepali prime minister Girija Prasad Koirala and aunt of Bollywood star Manisha Koirala, will set the stage for the visit to India next week of Nepali Prime Minister Madhav Kumar Nepal.

Koirala will focus on economic diplomacy during her visit, lobbying for greater Indian investment and cooperation as well as the signing of three important economic pacts.

The foreign minister will open talks for a key revision in the India-Nepal Trade Treaty, which comes up for renewal in 2012.

In the 70s, the two neighbours had a single trade and transit treaty for bilateral trade which was later broken up into two separate treaties for convenience.

While the transit treaty is renewed every seven years, the trade treaty so far has to be re-inked every five years.

With Nepali investors saying the time frame is too short to benefit investors, the Nepal government had been seeking a 10-year shelf life for the trade pact.

Eventually, both sides have agreed to revise the treaty so that it will be renewable every seven years, Koirala said.

Power-starved Nepal has accorded top priority to hydropower and Koirala will be seeking fresh Indian investment in the sector as well as in infrastructure and other key areas.

With the fate of earlier Indian investment in Nepal's thorny hydropower sector uncertain, Koirala will open negotiations for the signing of a Bilateral Investment Protection Agreement.