The cars - Zest, a compact sedan, and Bolt hatchback, will be powered by the company's new Revotron engine series.
These two new products are based on the company's enhanced X1 platform, on which the existing Vista and Manza models are built.
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"These cars have been engineered for global markets, through global teams across India, the UK and Korea to set new standards in their respective segments," Tata Motors President Passenger Vehicles Ranjt Yadav told reporters here.
The journey has just started and with these two new vehicles the company would like to increase its market share, he added.
"With these two cars, the important part is that we would now be able to address petrol car market," Yadav added.
After launching the cars in India, the company will be introducing the products in other global markets, Yadav said.
When asked if the company would phase out Indica and Indigo, Tadav said: "Both Indica and Indigo are very strong brands and will continue to sell in the market."
Both the new cars have been a result of collaborative design inputs from the three Tata Motors design studios in Pune, Coventry (UK) and Turin (Italy), the company said.
Zest would be available in both petrol and diesel versions, while Bolt will come only with petrol engine.
The diesel variant of Zest will come with F-Tronic 90 PS powered engine.
The cars would be produced at company's Pune plant in the first phase and meet Indian safety standards.
"The cars would adhere to country specific regulatory conditions, whenever we start exporting the cars," Yadav said.
When asked about improvement in sales, he said the full impact would be felt as the new cars will hit the market only later this year.
Both the new cars have various new features including the EPAS (electronic power assisted system).
Tata Motors has been struggling to arrest slide in its car sales amid a prolonged slowdown in the domestic market.
In January, the domestic passenger vehicle sales of Tata Motors dropped to 10,974 units, from 15,209 vehicles a year earlier.
Tata Motors sold 8,463 units of Nano, Indica and Indigo cars and 2,511 units of Sumo, Safari, Aria and Venture vehicles in January.
Tata Motors shows off first new cars in four years
India's largest carmaker Tata Motors unveiled its first new models in four years on Monday, banking on two small cars to reverse the company's sliding passenger car sales in the face of growing foreign competition.
Sales of Tata passenger vehicles in India fell an annual 37 percent in the first nine months of the fiscal year that ends in March, according to data from Society of Indian Automobile Manufacturers (SIAM), the steepest drop in an ailing industry headed for a second straight year of declining sales.
Rising interest rates and high fuel costs in Asia's third-largest economy, growing at its slowest pace in a decade, have pushed consumers to delay the purchase of big ticket items.
In a bid to revive its fortunes, Tata is pinning its hopes for now on the all-new Bolt hatchback and Zest entry-level sedan to tap into the small car market that accounts for the bulk of passenger vehicle sales in India.
Last year, the India autos giant watched as its rivals launched a number of popular models, including Honda Motor Co with its entry-level sedan Amaze and Hyundai Motor Co's Grand i10 hatchback. Tata, meanwhile, only tweaked and refreshed existing models.
Small cars are top sellers in a country where most people prefer to drive cheaper, fuel-efficient compact cars as roads are clogged with traffic and parking in big cities is hard to come by.
Tata will showcase the Bolt and Zest, to be made at its Pune factory in western India, at the Indian auto expo that starts on Wednesday.
"Clearly the compact sedan and the hatch present the biggest opportunity from a market standpoint," said Ankush Arora, Tata Motors' senior vice president and head of the commercial-passenger vehicle business unit, said on Monday.
Over the last two years, Tata has relied on strong performance at its luxury Jaguar Land Rover unit to offset weak sales at home, where it is losing market share to Hyundai Motor, Maruti Suzuki and others.
FRESH DESIGNS NEEDED
Monday's unveiling of the new Tata cars came just over a week after Karl Slym, who was the company's managing director, died after falling from the 22nd floor of a Bangkok hotel, in what police said may have been suicide.
The cars would have been the first new passenger vehicles to be launched under the leadership of Slym, who joined Tata in October 2012 and was tasked with reversing the sales slump.
While his death has caused worries about potential delays to the company's turnaround plans, Tata Motors has said it has a pipeline of products through the next six years.
"What Tata Motors really needs is fresh designs. So far it has been depending on slight changes and model extensions," said Anil Sharma, an analyst with IHS Automotive.
"It doesn't matter which model or what segment they are targeting. It's absolutely critical for them to start somewhere and this is a positive move for them."
The company has not launched an all-new Tata-branded passenger vehicle since its Aria crossover in 2010.
Last month, it unveiled the first variant from its new series of petrol engines, which will power some of its future cars, including the Bolt and Zest. Most of Tata's passenger vehicle sales are for diesel-powered models.
Tata Motors, India's largest maker of trucks and buses, has been posting losses in its domestic operations for the last few quarters, but strong JLR sales have rescued it.