VIRGIN Australia and Air New Zealand will offer the first direct service between Perth and Christchurch for two decades when they start twice weekly peak-season flights between the cities in December. The new route, which will be operated by an AirNZ Boeing 767 in the December-April high demand season, was announced last night by Air New Zealand chief executive Christopher Luxon at the opening of new terminal facilities at Christchurch International Airport. The partners are seeking an extension of their trans-Tasman alliance and have called for capacity conditions to be lifted.