There is no need to panic.

不必惊慌。

《新英汉大辞典》

There is no need to panic, but there is a need for a call for action.

没有必要惊慌失措，但是确有必要呼吁人们行动起来。

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There are ways to minimize radiation exposure, and there's no need to panic.

总是有减少辐射暴露的方法，所以没有必要引起恐慌。

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Water utilities see no need to panic, but consumers seem determined to take precautions.

CNN: Y2K fears open flood of bottled water sales

But there's no need to panic just yet, says Devon Reese(ph), president-elect of the Greater Las Vegas Association of Realtors.

NPR: Real Estate: A Long Suit in Vegas?

There is no need to panic, however: the creatures in question are harmless bacteria that were found preserved in a crystal of rock salt.

ECONOMIST: Old salts