China's exports and imports rose in April from the year-ago period, government data showed on Thursday, defying expectations for a dip in both figures.

Exports climbed 0.9 percent on year in April, the Customs Administration said, much better than the 1.7 percent dip a Reuters poll of analysts had predicted and versus March's 6.6 percent fall.

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Imports rose an annual 0.8 percent, against a Reuters forecast for a 2.3 percent drop and compared with an 11.3 percent slump in March.

This brought the trade surplus for the month to $18.5 billion, more than double the $7.7 billion in March.

The market reaction was swift as investors cheered the data: Chinese shares ticked higher, Japan's Nikkei (Nihon Kenzai Shinbun: .N225) widened gains to more than 1 percent, while the Australian dollar (Exchange:USDAUD=) hit a fresh two-week high.

According to Timothy Riddell, head of global markets research for Asia at ANZ, while the numbers are positive, what's key is if the momentum is maintained.

"It's the duration of [trade] bounce back that's going to be critical. Is this going to be a short-term cyclical recovery from a poor first-quarter? [If yes] then we're still going to be worried about what happens for the second-quarter," Riddell said.

Others warn against reading too much into one month of data, especially as the country shifts towards domestic consumption and away from investment-led growth.

"I think the export as an aggregate is a minor contributor to the GDP (gross domestic product) so I would think that export number would not be a good indication for the economy now," Kelvin Wong, China and Hong Kong equities analyst at Julius Baer (Swiss Exchange: BAER-CH), told CNBC.

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There are also concerns the trade numbers, which are known to be volatile, could be distorted by fake flows of cash pouring into China.

"As warned by officials last month, that trade data right now is not reflecting what is going on partly due to exports [being] hurt by over-invoicing which has been a popular way of getting capital in and out of China," said Luza Silipo, chief economist for Asia Pacific at Natixis (Euronext Paris: KN-FR).

However, Silipo notes that the trade figures do provide valuable insight into the extent of impact to the economy in the rebalancing process.

"Before China really becomes domestic driven, it will take some time and in this time, trade and exports will provoke some slack," he said. "The most important information that trade figures is giving is how quickly the transition is happening and how much slack we have to fill."