Auckland councillors have been summoned to an extraordinary meeting today to approve $1.5 million to pay the balance of $1.271 million and provide a contingency for "any unforeseen circumstances".
Mayor Len Brown said the extra funding would ensure the ongoing success of the cup as attention focuses on Auckland, where six of the last eight matches will be played.
"I'm determined nothing is going to change over the next three weeks as world attention is truly focused on Auckland," Mr Brown said.
A report to the council said the final three weeks of the tournament would see increasing numbers of supporters use the waterfront and three regional fan zones at Albany, Henderson (Trusts Stadium) and Mangere.
The unprecedented level of activity and lessons from the opening ceremony have resulted in the need to expand existing plans, the report said.
This will involve the creation of a new fan zone in the Madden St carpark at Wynyard Quarter with a capacity for 7500.
The combined capacity of Queens Wharf, Captain Cook Wharf and Madden St is 30,000.
The Wynyard Quarter fan zone will be set up in a block of Madden St directly opposite Silo Park. It will have Rugby New Zealand 2011 branding, at least one giant television screen and food vendors. It was unclear last night whether it will be licensed to sell alcohol.
The fan zones at Albany Lakes and Trusts Stadium are licensed, but at the request of the Mangere community no alcohol will be available at the fan zone there. The regional fan zones will be open only at weekends.
The Auckland Management Committee, which has drawn up the plans, also believes it is a "prudent precautionary measure" to have a contingency plan to double the capacity of the Mangere fan zone.
The three regional fan zones will be open for the last three weekends of the tournament.
Auckland ratepayers have already spent about $102 million on the cup - $65 million for infrastructure and $37 million for running costs and for events such as the $2.7 million opening-night extravaganza.
Because the council has not provided any fat in the running costs for the cup, it is looking to fund the $1.5 million through cup cost savings or wider council savings.
Councillors and ratepayers were given repeated assurances by Auckland Tourism, Events and Economic Development (Ateed) that it had planned for every scenario at the opening ceremony.
The extra $5.5 million does not include additional costs incurred by Auckland Transport and, last night, a spokesman did not know how much these would be.
Precautions
Where the money goes:
$2.16m Captain Cook Wharf
$1.66m Quay St
$805,000 Wynyard Quarter fan zone
$66,000 additional activities on Queens Wharf
$300,000 additional activities at Wynyard Quarter
$280,000 extension of Mangere fan zone
$5.5m total, incl. contingencies.