Within 10 years Auckland light rail routes could include Silo Park to Auckland Airport and Auckland CBD to Westgate.

Auckland motorists may be digging into their wallets within six months in order to pay for a new fuel tax aimed at funding billions in transport infrastructure.

Mayor Phil Goff has welcomed the introduction of fuel tax and says the city "has to pay its share" in developing "desperately needed" projects, including a light rail link between the CBD and the airport.

The tax is likely to be 10c a litre.

SHANE WENZLICK/STUFF "If you can't even get to job interviews on time because of late buses then something must be done," Darryl Evans said.

"Light rail will help decongest our roads and provide a 21st century gateway to visitors to Auckland. It will also allow for more intensive housing development around transport hubs bringing economic benefits to those suburbs it travels through," Goff said.

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"A fuel tax is effective and cheap, and easy to administer. It will help ensure that Auckland can pay its share of the nearly $27 billion expenditure on transport infrastructure over the next 10 years.

"Without this level of investment our rapidly growing population will worsen congestion on our roads with mounting costs from frustration and lost productivity."

Incoming Transport Minister, Labour's Phil Twyford, said the fuel tax would contribute "about 10 per cent" of an expected $15 billion, 10-year Auckland transport programme.

However, Mangere Budgeting and Family Support chief executive Darryl Evans said the city's poorest families will be amongst those hardest hit if the new tax spikes petrol prices.

BRADEN FASTIER/STUFF Green-lighting light rail will give "Aucklanders a congestion-free, alternative to driving, to get roads moving again," incoming Transport Minister Phil Twyford said.

Since poorer families tended to live in the southern and western most suburbs, they also often faced the longest commutes to jobs and a petrol tax cost them heavily.

For those who have no choice to drive, they will start pooling car use with friends and family to share costs.

"Traditionally, when fuel prices go up people will use their car an awful lot less," Evans said.

JAMES PASLEY/STUFF Key central Auckland arterial Dominion Road has long been a rush-hour commuter choke point.

But it was also in the best interests of those families to have improvement of the super city's public transport services, because the status quo of long journeys caused by road congestion and fragmented bus routes hurts them most, Evans said.

"We can't get our clients into jobs because of poor public transport,

"If you can't even get to job interviews on time because of late buses then something must be done."

KEVIN STENT/STUFF Lumping-on an extra 10c per litre on petrol, on top of GST's existing 15 per cent, means the poor will pay more, the Child Poverty Action Group said.

Many of his service's south Auckland clients want to work in Auckland CBD or further but can't because of poor public transport, Evans said.

One client said he had to catch three connecting buses to and from his minimum-wage CBD job.

The new Labour/NZ First coalition government's promised minimum wage hike to $20 per hour would offset higher Auckland petrol and public transport costs, Evans believes.

JASON DORDAY/STUFF The push for a regional fuel tax started under Len Brown.

Child Poverty Action Group communications officer Jeni Cartwright said the group agrees transport services need improving but services like light rail need to reach into south Auckland.

Lumping-on an extra 10c per litre on petrol, on top of GST's existing 15 per cent, means the poor, with lower discretionary income, will pay more.

A more "progressive" tax system should be considered meaning those who can afford to pay more do so, Cartwright said.

SIMON MAUDE/STUFF Letting Auckland have a fuel tax "has pushed the decision back to council to see if they want to do it, the political pressure is now on them," Greater Auckland's Matt Lowrie said.

LIGHT RAIL DOUBLE-DOWN

Central to Labour's plans is a "21st century, rapid-transit network" including light rail, or trams, along key Auckland roads, Twyford said.

"It will give Aucklanders a congestion-free, alternative to driving, to get roads moving again."

SIMON MAUDE/STUFF "We want to see really clear [public transport] business cases, we'd like Aucklanders to have a say on it," the Automobile Association's Barney Irvine said.

Twyford said the Government will change the law to allow a regional petrol tax and then it will be up to Auckland Council to decide when it wants to levy the tax.

Both current Auckland Mayor Phil Goff and his two-term super city predecessor Len Brown pushed for a fuel tax only to fall on deaf central government ears.

The nine year John Key and then Bill English-led National government consistently ruled-out introducing such a tax.

Twyford set his timeframe for passing the legislation as "within four to five months."

Council controlled Auckland Transport is currently investigating several light rail routes from Auckland waterfront's Wynyard Quarter through Manukau and Dominion Rd's to Auckland Airport.

Labour has gone further, its election manifesto includes installing light rail from the CBD to west Auckland's Westgate within 10 years.

Auckland Transport and NZTA had investigated a busway for the same route.

Greater Auckland public transport lobbyer Matt Lowrie said the new government's decision "makes a lot of sense".

"It has pushed the decision back to council to see if they want to do it, the political pressure is now on them."

SHOW US THE BUSINESS CASE

Influential lobby group the Automobile Association is not "in principle" opposed to an Auckland regional fuel tax.

Its infrastructure and Auckland transport spokesman Barney Irvine said business cases for expensive public transport works like light rail must be consulted on.

"We want to see really clear business cases, we'd like Aucklanders to have a say on it."

Auckland Council's Long Term Plan out for public consultation next year is a good opportunity to ask Aucklanders, Irvine said.