Special permission has been granted for six experts from Germany to fix a broken Wellington water pipe.
The pipe in the suburb of Berhampore burst beneath Mt Albert, making it impractical to carry out excavation.
The city council says the safest and most durable option is to use a polyester liner, which has been designed and manufactured by a specialist engineering firm in Germany.
Experts from the company will arrive in the middle of this month and go into isolation in self-contained accommodation, with food and other essentials delivered to them.
The work is likely to begin early next month and be completed a few weeks later.