Chinese and German manufacturers have been short-listed to build what will be New Zealand's longest new tunnel boring machine for Auckland's $4.4 billion City Rail Link.

Sean Sweeney, CRL chief executive, said the Link Alliance would this month pick who would supply the machine with its fierce 7.15m diameter cutting head. Offers have been submitted from Germany's Herrenknecht, which built the Waterview project's Alice, and China's CREG.

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