(Adds business sentiment, govt comments)
SEOUL, May 1 (Reuters) - South Korea posted its first monthly trade surplus this year in April, with buoyant exports of wireless handsets and automobiles countering a fall in shipments of chips and computers, government data showed on Thursday.
The contagious SARS virus has so far had little impact on exports but is likely to begin taking a toll on overseas shipments, the Commerce Ministry said in a statement.
"From May, the SARS and a possible rise in labour dispute will be major variables to exports and, therefore, it is uncertain if we can sustain a trade surplus," it added.
The Severe Acute Respiratory Syndrome hit China and the neighbouring region, which together account for about a quarter of total exports.
The trade balance swung to a surplus of a provisional $1.01 billion in April from a deficit of revised $514 million a month earlier.
Exports rose 20.3 percent on the year to $15.9 billion, while imports grew by a slower 18.2 percent to $14.9 billion.
Separately, the country's top business lobby group said its business confidence index rose for May, snapping a seven-month decline, but still more companies were expecting a worse future than those expecting a better one.
The rebound in the business survey index, its first rise since September last year, is attributable to a sense of relief from a swift end in the U.S.-led war in Iraq, the Federation of Korean Industries said in a statement.
The index for May rose to 90.2 after seasonal factors from 81.7 for April. Before seasonal factors, the index stood at 108.1 for May versus 90.2 for April, the federation said.
An index below 100 means more companies were expecting their business conditions to worsen in the coming month than those foreseeing a better month.