Whenever we have significant rainfall, we have water seeping up from underneath pur concrete slab around where the pipes pass through the slab. The pipes have a thin layer of foam wrapped around them between the pipe and concrete and this seems to let the water soak up and then into the concrete base beneath the tiles, it then spread through the concrete under the tiles and seeps out underneath the timber wall framing into adjacent rooms.
Do we require our whole bathroom to be pulled up and the plumbing and floors resealed? Who's fault is this our builders, the plumber that did the bathroom plumbing installation or the tilers?
Any assistance would be apprediated as we are sick and tired of this constant flooding.

Sounds to me like you have insufficient drainage around the perimeter of your home, and the water is puddling around the sides of the slab. This would cause the water pressure in the ground (under your slab) to push upward (seeking the equal the water level that is outside). Concrete is porus and will allow the water to pass through, but the easier route is for the water to come through where the pipes are. If I am correct, your problem is outside your home... you need good rain gutters with downspouts connected to underground drainage pipes to carry the water as far as possible from the foundation. You also need the ground runoff to channel water away from your home, perhaps in the same drains as for the downspouts.

The plastic foam around the pipes is most likely to reduce corrosion from the contact with the concrete directly to your pipes.

I would assume that the builder would be responsible for grading water from the home, but it depends on local laws, how old the home is, and whether you've changed the grade at all. Perhaps a kindly worded question to your builder would be a good place to start.

I agree; it's certainly not the plumber or tiler's fault, and a key question is when was the house built?
Have you made a changes to the landscape that would increase water around and under the house, such as paving that allows water to head for the house, or planting trees that might have clogged your underground drainage after 5 - 10 years?

Agree with above statements. You need to do something to get that ground water drained away from the foundation of the house.
It is code everywhere that I know of to wrap any plumbing pipes coming up through concrete to keep separation of the pipe and concrete. Without this separation, the slightest settling of slab or under ground will break the plumbing pipe. If this is an older home and you can't afford to install an outside drainage system, you may start by having a sump pit and pump installed in the basement to eject ground water. But at the very least you will need to do a little landscaping to direct water away from home.