The council's strategy and finance committee was told that a publicity campaign would take place assuring card users not to panic about the expiry date.
Marie Gorinski, a council policy analyst, told the committee the cards had been printed with an April 30, 2013 expiry date before the council decided to make the scheme permanent.
Ms Gorinski said that since the cards were introduced there had been a drop in parking revenue in the CBD but this could not be solely attributed to the SuperGold cards.
She said parking patterns had changed, the current economic climate was probably another impact, and some elderly people eligible for the card may have stopped driving.
"In passenger transport there is evidence to show that bus trips are increasing with the use of SuperGold cards for free bus travel," Ms Gorinski said.
She said the display card had proven to be "extremely popular" with the city's elderly and there was strong support for the scheme remaining.
However, the concession parking had created more work for council staff, especially when some drivers forgot to display their card. They would have been issued with a parking ticket which was later nullified once they produced their SuperGold card at the council office.
Ms Gorinski said there were still some 2000 unused cards and any expiry dates would be deleted before they were given out.
In the meantime, the council will carry out a publicity campaign through local media, community forums and older people networks explaining that card users should simply ignore the expiry date from the end of this month.