Support is re-igniting for a Wellington to Auckland sleeper train, as air fares soar.

The idea was floated at a Wellington council meeting last week.

Greater Wellington Regional Council climate chair Thomas Nash says tracks between Auckland and Wellington are seriously under-utilised.

He says night trains are popular overseas, particularly in Europe, as a more affordable and lower emission option.

"Night trains are absolutely cranking at the moment, more and more services are opening up. They're really well-patronised - and that's partly because of the cost of flights."

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