Japanese carmaker Suzuki Motor will invest 350 billion rupees ($4.21 billion) to build a second car plant in India's Gujarat state, its president said on Wednesday, aiming to raise production capacity in one of its key markets.

Suzuki will also invest 32 billion rupees to add a new production line in an existing plant in the state, which will boost its electric vehicle production, Toshihiro Suzuki said at an investment summit in the state.

India's thriving auto market is key for Suzuki where its subsidiary Maruti Suzuki is the top carmaker by sales.

Suzuki's annual production capacity will increase to 2 million units in the state as a result of the new investments, the company said in a statement.

($1 = 83.1675 Indian rupees) (Reporting by Aditya Kalra; Writing by Shivam Patel; Editing by Christopher Cushing and Kim Coghill)