Water Leakage At Soffit of the Slab

A picture is worth a thousand words or in this case eighty eight words.

Why only where you cured your plaster (is there a specific reason for this?) and is this re-plastering or what? As asked previously, a picture is worth a thousand words...slightly less in your case perhaps

It's a newly plastered wall and we had applied a water curing on it by a pressurized hose. Water was accumulated on the floor (structural slab) and we found out later that the water has leak everywhere in the soffit of the slab. Is there any structural effect on the durabilty of the concrete if the leaking persist coz curing will last for a minimum of 7 days?

Water (some of it) is bound to to seap through the slab during curing. Structural damage may occur if the water was hosed before the concrete gained its minimum strength, which I suspect to be the case here. You will need to allow the concrete slab to receive its maximum strength requirement (per engineer) before taking off the formwork. Furthermore, screeding and waterproofing will also have to be undertaken as per normal building regulations applicable to your area (the wet area should be allowed to dry)

First, most concrete, depending on the exact make-up of it's constituent materials in the mixture, has to some extent a measure of porosity which can permit allow permeation of water through it's non-homogeneous structure.

Secondly, I suspect that the slab soffit may not have been properly sealed before the application of of the plaster and subsequent water curing. Is the slab dead level in this area where you're experiencing the wetness? If the water has no where to flow due to any slab flatness, you can practically guarantee that it will pass through the slab.

Thirdly, you may have concrete shrinkage cracks of sufficient width and depth to allow passage of the water.

check the gutters for leaks. french drain? landscape that slopes away from the building.

_{I hope the problem has been resolved now.As said above the slab Soffit may not have been sealed properly.My friend have the same issue and he pefer hiring a Slab Leak Detection company as specialist has visited their home and repaired those leaks.}