Former government minister Michael Bassett has criticised Auckland Council for the planned City Rail Link, saying the $2.8 billion project would drive up rates and should be prioritised behind a second harbour crossing.
Bassett - who was local government minister in the 1980s - said the "profligate" council would be forced to borrow more money or put the burden on ratepayers to fund the tunnel.
"Planning a second harbour crossing is much more urgent - absolutely vital in the very near future," he said.
"This council has a big appetite and many expensive ideas. Now, the mayor wants government money (taxpayers' of course) for an early start on his great white elephant, the underground rail route.
"It will never make money. It won't even cover its costs. The mayor will then either demand bigger subsidies from the Government for the shortfall in revenue, or he'll push up our rates to pay that shortfall, or borrow yet more money.
"Public transport in the Auckland region already gets a huge subsidy. And it will need more to pay for the white elephant."
A spokesman for mayor Len Brown responded by saying there was "no doubt" the rail link was Auckland's most urgent priority.
"Without the City Rail Link, both Auckland's bus and train networks will reach capacity by 2021 with average peak time speeds of 7km/h in the city centre, costing billions in lost productivity and creating a major headache for Aucklanders," he said.
The mayor would welcome any early start to the Additional Waitemata Harbour Crossing project, the spokesman said.
Bassett said the second harbour crossing could be funded by tolls and/or a congestion charge.
"A more honest approach would be user pays for the two crossings," he said.
The Government said last year a second bridge was likely to be needed between 2025 and 2030.
Auckland council wants construction of the CRL to start in 2016 but the Government said it will have to wait until 2020, unless CBD employment grows by 25 per cent or rail patronage heads toward 20 million trips a year before 2020.