The commission found that any regulatory concerns were outweighed by the economic benefits to Singapore.
The deal between the two state controlled airlines could start as soon as December once New Zealand transport minister Gerry Brownlee gives approval.
The Auckland-based airline and the Asian carrier plan to boost capacity between New Zealand and Singapore by 30 per cent with the tie-up, which will see Air New Zealand return to the Asian city state for the first time since 2006.
The airline will take over five flights currently operated by Singapore Airlines, which will maintain its daily Singapore-Christchurch service as part of the deal.
Last month budget carrier Jetstar announced it was abandoning the Auckland-Singapore route after trimming flights to three times a week 18 months ago amid falling demand.
Air New Zealand and Singapore Airlines are both major shareholders in Australia’s Virgin Airlines, along with fellow Air NZ partner Etihad Airways.
Singapore Airline passengers will be able to travel across Air New Zealand domestic and some international routes, while customers with Air New Zealand will have access to similar codeshare travel across Singapore Airline’s South East Asia, UK, Europe and Africa networks.