NEW DELHI (AFP) - South Korea's president arrives this Wednesday in India on an official visit during which she is expected to push for some of the South Asian nation's nuclear business, officials said.

India and South Korea, two of Asia's biggest economies, struck a civilian nuclear agreement in 2011 and now Seoul is exploring possibilities for a nuclear project.

The South Korean President Park Geun Hye is due to arrive on Wednesday and is leaving on Jan 18.

The first time South Korea raised the subject of building a plant officially was during a 2012 meeting between Prime Minister Manmohan Singh and Park's predecessor, Lee Myun Bak.

But India has indicated it would first want to see a demonstrator unit because it is not acquainted with Korean nuclear plant design.

"We haven't even got into the feasibility issues (of a plant) so the issue of identifying possible sights (for the project) only comes after that," foreign ministry spokesman Syed Akbaruddin told reporters.

"We'd desire on part of the India's department of atomic energy to first consolidate the civilian nuclear programme before looking at new rights and (nuclear) programmes," the ministry spokesman added.

Park will be visiting India days after the country's environment ministry gave the go-ahead for a Posco steel plant in the eastern state of Orissa, nearly a decade after the project was first agreed.

Posco has acquired land needed for the project and "very recently environment ministry too has given its clearance for the next five years. With this, we hope the Posco project can move forward," the spokesman said.

But the eight-million-tonne-a-year plant's captive port and related infrastructure projects still need clearance.

In other areas such as defence and security, Delhi-Seoul ties have been forging ahead.

"We do have a wide ranging defence relationship, working together on defence research and development, anti-piracy operations in the Gulf of Aden besides joint naval exercises with South Korea," the foreign ministry spokesman said.

India is poised to make the first purchase of South Korean military equipment in the form of minesweepers, local media reported.

South Korea is also expected to seek more access to Indian markets especially for auto and steel, reports say.

The two countries signed a Comprehensive Economic Partnership Agreement in 2009 but Seoul believes rival Japan got a better deal.