Virgin Blue Holdings will purchase at least 105 new Boeing 737 jets over six years to replace its old planes and to offer new flight routes. The new planes are to be delivered starting June 2011 up to 2017.

The deal is Virgin Blue’s largest plane order in its 10-year history. The Brisbane-based airline company said in a press release on Thursday that a significant percentage of the new jets are intended for replacement of Virgin Blue’s existing narrow-body fleet. Meanwhile, the remaining planes will be used to boost flight frequency and for new routes.

The Centre for Asia Pacific Aviation (CAPA) said that the company’s massive order only shows Virgin Blue’s strategy to compete against rivals Tiger Airways, Qantas and Jetstar. CAPA added that Virgin Blue will be marginalised in the future if it failed to expand and compete effectively.

In an interview with the CEO of Virgin Blue, Brett Godfrey did not disclose the price of the order. However, he said that the new jets were purchased on ‘attractive commercial terms’. Godfrey also added that Virgin Blue will finalise its funding arrangements for the deal shortly.

As of December 2009, the airline group – consisting of Virgin Blue, Polynesian Blue, V Australia and Pacific Blue – had 87 planes, of which 62 were Boeing 737-700/800 models. The airline group also has four Boeing 777-300ER jets flown by long-haul airline V Australia to Thailand, Fiji, South Africa the US. A fifth plane is expected to be delivered in November.