Johannesburg — SA's trade deficit doubled to R10bn last month, buoyed mainly by a huge leap in the bill for oil imports, which climbed to a record R16,9bn on the back of rising global prices.

The shortfall was the highest in three months and above consensus forecasts of a R6,5bn deficit, but the figures are notoriously volatile.

"It was quite a shocker," said Standard Bank economist Shireen Darmalingam. "It leaves the country's external position in a very tough spot."

She was referring to the gaping deficit on SA's current account, its broadest measure of trade in goods and services, which widened to 7,3% of gross domestic product (GDP) last year, a 36-year peak, and is likely to expand to 8% this year.

That is a worry, given that capital inflows into SA have slowed in response to global risk aversion and concern about its pace of growth, which is likely to slow to close to 3% this year from about 5% over each of the past four years.

The rand weakened to R7,63 to the dollar from R7,59 after the data from the South African Revenue Service, which showed that imports and exports rose to record levels last month.

Overall imports jumped almost 18% to R66bn, partly reflecting a 14,3% rise in the influx of machinery and mechanical products, stemming from demand sparked by an infrastructure spending programme.

Exports rose almost 10% to R56bn, but would have been higher if not for the effect of power outages on mining output, which cut exports of precious stones and metals.

"This confirms fears that the trade deficit will remain under pressure from higher oil prices, and from imports especially of diesel," said Goldman Sachs economist Ashok Bhundia.

International oil prices have risen about 34% so far this year, and demand for diesel has been spurred by purchases of generators by households and businesses hoping to avoid the effect of power outages.

The cumulative trade deficit for the first four months of this year rose to R31,6bn from R20,9bn in the same period last year. "This means that even amid a deceleration in growth,

SA's trade balance is still a concern," said Razia Khan, Standard Chartered's regional head of research for Africa.

"At least economic growth will be supported by activity in construction, but a widening trade deficit will ... ultimately be bad news for growth and the rand."

Economic growth slowed to 2,1% in the first quarter from 5,3% in the final quarter of last year. However, construction rose 14,9%.

Darmalingam said the figures showed that the import cover ratio of SA's gold and foreign exchange reserves fell to 3,9 months last month from 4,9 months in March.

The relative strength of the rand in the second half of last year gave the Bank the opportunity for "robust" purchases of foreign exchange, but its depreciation this year would hamper the trend, she said.

The rand has weakened about 10% against the dollar this year .