WASHINGTON (AFP) - US economic growth in the fourth quarter was stronger than originally thought at 0.4 per cent, the Department of Commerce said on Thursday in its final revision of the initial estimate.

The previous estimate had the economy basically flat, expanding at an 0.1 per cent annual pace.

The new data showed exports and business investment in structures and equipment both higher than previously expected. But the revised data on personal spending were lower than earlier estimates.

However, the department added, growth was still sluggish and "the revision to GDP has not changed the general picture of the economy". The 0.4 per cent fourth quarter pace came in after a solid third quarter expansion rate of 3.4 per cent.

Overall in 2012, gross economic product expanded 2.2 per cent, a modest pace that left policy-makers still frustrated at the slow growth in jobs and the substantial government budget deficit.

Economists believe the economy picked up in the first quarter of this year ending Sunday, with estimates close to the average for 2012 despite the onset of higher taxes from Jan 1 and the federal budget-crunching "sequester" spending cuts that were launched from March 1.

BMO Capital Markets economist Jennifer Lee called the revised fourth quarter rate "still disappointing" but said the investment bank was sticking by its forecast of growth holding 2.2 per cent for 2013.