Blue smoke from Turbo Diesel Ute?

When I turn my Turbo Diesel engine on (Ford Courier 1999) it spits out load of blue smoke on startup. Also seems to only spit out blue smoke on idling, upon applying accelerator, the smoke disappears until idling again.
Any recommendations on how I can troubleshoot the culprit? The Turbo is held together with Duct tape at the moment. (from previous owner) So i'm unsure if that is the cause.

It is just as likely to be worn valve guides and seals. It's 19 years old after all. Either remove the head and turbo for refurbishment or trade it in. Whichever is the most economical.

BLUE SMOKE is an indication of oil being burnt. At cold start, blue smoke usually reflects poor oil control. Obviously, it should not be present at any time. The oil can enter the combustion chamber for several reasons. Worn valve guides or seals is the most common. Wear in cylinders, piston rings, and ring grooves, or piston rings sticking in grooves, or cylinder glazing might also be indicated and are expensive to fix. Faulty turbocharger seals, incorrect grade of oil (eg oil too thin, and migrating past the rings) or fuel dilution in the oil (oil thinned out with diesel) are less expensive problems to address. It is worth noting, that engines with good compression can burn quite a lot of oil without evidence of blue smoke when accelerating or cruising at speed, so hopefully you can rule out piston/ring/cylinder wear as the main trouble.

Possible cause. When I had a similar problem with an old Peugeot diesel, it was eventually found to be due to a sticking / not shutting off fuel injector. It allowed some fuel from residual fuel pressure to leak into one cylinder when the engine was switched off and pass too much fuel when idling. This gave gave exactly the problem you describe and a replacement injector cured it.

Sure, have the engine rebuilt.

Duct tape barely holds ducts together, let alone a red-hot turbo. The engine is worn out.