WASHINGTON, June 24 (Reuters) - The U.S. current account deficit widened more than expected in the first quarter amid a shortfall on the primary income balance, government data showed on Wednesday.

The Commerce Department's Bureau of Economic Analysis said the current account deficit, which measures the flow of goods, services and investments into and out of the country, increased $5.8 billion, or 2.6%, to $226.8 billion last quarter. 

Data for the fourth quarter was revised to show the deficit at $221.1 billion instead of the previously estimated $190.7 billion. Economists polled by Reuters had forecast the current account deficit widening to $215.0 billion.

The first-quarter current account deficit represented 2.9% of gross domestic product, up from 2.8% in the October-December quarter. It peaked at 6.3% in the third quarter of 2006. The current account deficit has no impact on the dollar given the greenback's status as a reserve currency.

The primary income balance slipped into a $13.3 billion shortfall last quarter from a $3.431 billion surplus. That partially offset a contraction in the trade deficit to $165.8 billion from $177.3 billion in the October-December quarter.

Primary income receipts dropped to $396.1 billion from $402.2 billion in the prior quarter. Primary income payments jumped to a record $409.1 billion from $398.8 billion in the fourth quarter. 

The report also showed a $3.3 billion increase in capital-transfer receipts to $3.4 billion last quarter, while payments fell $0.9 billion to $2.0 billion. The U.S. maintained a negative net international investment position, which is the difference between U.S. residents' foreign financial assets and liabilities.