Virgin Australia said on Thursday that it inked a $2.2 billion deal with U.S. aircraft manufacturer Boeing for the delivery of 23 737-MAX-8 over the next 10 years, beefing up the fuel-efficient fleet of the country's second-largest carrier.

In a statement, Virgin Australia Chief Executive John Borghetti said the new acquisitions will amply support the company's thrust, which was implemented since the early 2000s, with core emphasis on "reliability, comfort and fuel efficiency."

As published by Boeing, Mr Borghetti pointed to the lower fuel consumption and carbon emission attributed to the 737-MAX, which he added should "reduce fuel burn and CO2 emissions by 13 per cent over today's most fuel-efficient single-aisle aircraft."

He highlighted such glaring advantages as main reasons why Virgin had opted for the 737-MAX while its nearest competitor, Qantas Airways, trained its attention to the green aircraft put together by Airbus.

According to The Australian, Qantas is set to replace its old 737s with the Airbus A320-NEO, which like the 737-MAX was designed to achieve more fight mileage with little fuel use and pollution.

"The Boeing 737-MAX will build on this (thrust), enabling us to achieve strong on-time performance and maintain our low cost base," Mr Borghetti was reported by Business Day as saying in his statement.

Virgin said delivery of the new plane orders should commence by 2019, with target of completing the whole batch by 2021.

However, the new agreement between Boeing and Virgin would lead to adjustments on the airline's previous 737-800 orders, delivery of which will be deferred after 2016.

But prior to the modifications, Virgin Australia said it still expects 31 737-800 units to join its fleet starting 2013 through the three years ahead.

The tweaks, according to Virgin, were solely meant "to align with its current capacity plan for the next three years."

The move also provides flexibility for the carrier "to respond to market conditions," and develop at the same time a uniform fleet of of narrow-body and wide-body aircrafts, Virgin said.