Airbus did tests at Wellington Airport with an Airbus A350 last June to test the runway - which is shorter than others it operates to - for its suitability.
Chief executive of Wellington Airport, Steve Sanderson, said with the connectivity Singapore Airlines provides, visitors from Asia and Europe are now spending $79m more per year in Wellington than before the service.
"There has also been a 37 per cent increase in visitors from Asia overall, with Singaporean visitor numbers up by 118 per cent, Indian visitors up by 105 per cent and Indonesia up 50 per cent.
The deployment of the A350-900s to Wellington follows an earlier announcement that Singapore Airlines will be increasing services on the Singapore-Melbourne-Wellington route to five times a week from January 1, next year.
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The airline has a joint venture with Air New Zealand which allows the airlines to co-ordinate flying and share revenue.
The deepening relationship will also result in more flying from Auckland to Singapore and Air New Zealand will operate out of Christchurch this summer to bolster services from this summer in addition to Singapore Airlines.
The A350-900 has higher ceilings, larger windows, and an extra wide body as well as lighting designed to reduce jetlag. Cathay Pacific already flies A350s to New Zealand and a number of other fly new generation Dreamliners which compete with the Airbus plane.
Singapore Airlines' A350-900 features 42 Business Class seats, 24 Premium Economy Class seats and 187 Economy Class seats.
Singapore Airlines' has a total of 67 A350-900 aircraft on firm order and as at October 1 had 41 of the aircraft in its fleet. The A350-900 has a list price of around $500m but airlines get substantial discounts, especially for large orders, of up to 50 per cent.
It has a special ultra long range (ULR) version of the aircraft to fly what is the longest commercial route in the world - Singapore to Newark, New Jersey.