Air New Zealand will increase its frequency from 12 to 14 services per week on its Boeing 787 Dreamliner aircraft from 29 March 2020 to 24 October 2020.
This brings the total number of services the two alliance partners operate to 21 per week.
Singapore Airlines will also deploy its larger A380 aircraft to meet strong demand over the Easter 2020 peak, replacing its scheduled Boeing 777-300ER aircraft.
Singapore Airlines Senior vice president marketing planning, Mr Tan Kai Ping, added: "Thanks to the joint venture we are, together, able to cater for the growing demand for travel to and from New Zealand that we have seen over the past 12 months.
"We are very pleased to be working closely with Air New Zealand to deliver a greater number of travel options to our customers between Singapore and New Zealand."