India's computer services sector defied growing cost pressures at home and a slower US economy to increase full-year revenues by an estimated 33 per cent, the industry's representative body said on Monday.

The National Association of Software Services Companies said total IT sector revenue, excluding hardware, would be $52bn for the year to March, of which $40.3bn would be from outsourcing services to other countries.

Som Mittal, Nasscom president, said :"While we are optimistic for the future, we need to be vigilant about how things are progressing".

India's IT outsourcing sector, one of the pillars of its recent economic boom, is coming under increasing pressure from domestic wage inflation, higher real estate costs and a stronger rupee.

The industry, which provides services from managing a client's computer systems to processing a foreign bank's mortgage applications, is bracing for a slowdown in its main customer base, the US financial sector.

Many of the large US banks have been hit by the subprime crisis and are expected to cut their IT budgets - expenditure on technology is always one of the first casualties in a slowdown because of its discretionary nature.

The banking, financial services and insurance industry accounts for about 40.4 per cent of India's export revenue from IT and business process outsourcing.

But Mr Mittal said India's outsourcing industry was holding up well and was on track to meet its forecasts of $60bn in software and services export revenue by 2010.