Policy actions is rather idiomatic, but I wouldn't go as far as to say it's an actual idiom.
The entire phrase means that economic policies must be changed to mitigate the coming trade imbalance, and that actions must be taken soon to implement such policy changes. Policy is used in a rather abstract sense; it does not mean that the actions that will be required soon should be in line with current policy, but should be representative of some trade/economic policy.
What policy actions means here, then, is actions implementing said policy.