Half of the $21.4 million spent on SuperGold Card public transport last year was in Auckland, although it is home to only one quarter of the country's senior citizens.
Over the year to July 2012, the NZ Transport Agency paid out $21.4 million for its 65 per cent share of the free off-peak travel subsidies - an 8 per cent rise from two years ago, despite changes to try to peg back the rising costs in 2010.
The scheme is now under review by the Ministry of Transport again as the Government prepares for Budget 2013 - when the current SuperGold Card funding is due to run out.
A regional breakdown of the costs released under the Official Information Act shows $10.7 million was spent on seniors travelling on Auckland ferries, buses and rail. That included the maximum amount of just over $1.5 million to Fullers for seniors travelling on the Waiheke Ferry - funding which was capped in 2010 after blowing out to $2 million a year.
The figures showed a 20 per cent drop of $550,000 in Canterbury in the two years since the earthquakes, but spending in Wellington rose by 22 per cent over the past two years to $1.4 million. Auckland had also increased by 8 per cent since 2009/10.
The Waiheke ferry cap, adjusted for inflation each year, meant Fullers has received no subsidies for some of its Gold Card passengers.
Fullers Group chief executive Douglas Hudson said the cap usually ran out between four to eight weeks before the next subsidy round each year, and the company absorbed the full cost of the free fares for that time.
"It does cost Fullers to carry those SuperGold cardholders once the cap has been reached," he said.
"However, we are comfortable with the degree of 'free' service we provide because we believe that overall, the advent of free ferry fares for SuperGold cardholders has been beneficial for the Waiheke economy."
Mr Hudson said it was impossible to calculate how many passengers would not have travelled without the Gold Card, but rejected claims the subsidies were extra revenue Fullers' would not otherwise have had.
He said many cardholders were either Waiheke residents or regular visitors who had bought tickets before the Gold Card was introduced.
The scheme has cost almost $100 million since it was introduced in October 2008 and extra funding had to be provided after it over-ran its original budget of $18 million a year.
A review in 2010 to trim the costs resulted in the subsidy to operators being cut from 75 per cent to 65 per cent, a cap on Waiheke ferry, and a freeze on adding new services, which runs out this year.
NZ First leader Winston Peters said the review for Budget 2013 was ominous given the National Government had already overseen changes in 2010 that had eroded the scheme.
He said its costs were well below original forecasts and the scheme was intended to be expanded. However, many people in the regions were missing out because a moratorium in 2010 meant new operators and services could not offer free fares.
NZ Transport Agency spokesman Andy Knackstedt said most of the subsidies were claimed in Auckland and Wellington because there were more transport options in big cities.
Regions in which the subsidy costs were well under their proportion of resident seniors included Waikato and the Bay of Plenty. Waikato spent just 3.2 per cent of the subsidy but was home to almost 10 per cent of over-65s and the Bay of Plenty spent under 3 per cent, but almost 8 per cent of seniors lived there.