Hi Niwantha, I see and hear both being used. For me, I would tend to use (1) because it keeps the passive voice structure "should be strengthened" intact. This is not a grammar rule but my stylistic preference. Another example: Both parties should communicate the ideas clearly. (Active voice) A: The ideas should be communicated more clearly. (Passive voice*) B: The ideas should be more clearly communicated. (Passive voice*) Personally, I would find sentence A easier to follow as the auxiliary and main verb are together, showing the modality of the main verb (should: a strong advice). * The subject (doer) is sometimes omitted in passive voice because their identity is not important or the reader already knows. I hope this helps.

They're both ok, Niwantha, but my own preference would be for the 2nd sentence.

1) is better, somehow.