He said another 11 cremations had been booked to take place today and tomorrow, so potentially 17 bodies could be returned if the gas was not restored by tomorrow.
"I suspect we'd have to be running a 24-hour operation for most of next week to clear the backlog."
Davis Funerals, which runs three funeral homes in Auckland is giving its clients the choice of cremating their loved ones at its Whangarei facility.
Manager Bob Russell said at least six of the 20 affected families had taken up the offer.
"At the moment, all crematoriums in Auckland are not operating. We're not charging them any extra and some of them would just like to have that closure."
The cause of the gas-line leak has been identified as a crack where pipes were welded together. Repairs are expected to take at least two days.
Mr Russell said that when cremations could not be held, "the bodies come back to the funeral director's chapel, and in most cases the bodies have already been embalmed so there is no problem".
Most funeral directors also had a cool room, "so we're well equipped to look after people in that situation".
But the grieving families might not be too happy if the situation continued.
Mr Russell said some crematoriums were looking at using bottled LPG gas, which might happen over the next two or three days if the repairs took any longer.
Auckland Council crematoriums were not operational yesterday, and the Council stopped heating its offices and buildings following instructions from Vector, which manages the gas line.
Spokesman Glyn Walters said the council was sourcing bottled gas for its crematoriums at North Shore, Waikumete and Manukau. "We expect minimal disruption to services."
Mayor Len Brown said the gas leak was a "major challenge" for Auckland and he has activated the Emergency Co-ordination Centre to co-ordinate the work of city departments and council-controlled organisations in a crisis.