British gas giant BG Group Plc (BG.L), a global leader in natural gas, said on Tuesday it agreed to sell its wholly owned QCLNG Pipeline Pty Ltd subsidiary in Australia to APA Group (APA.AX) for $5 billion (3.19 billion pounds).

The pipeline network, running 543 km long, links natural gas fields to the Queensland Curtis Liquefied Natural Gas (QCLNG) export facility.

The company said the deal is expected to be completed in the first half of 2015 and is conditional on the start of commercial LNG deliveries from the QCLNG export facility at Gladstone and on partner consent.

This is the biggest sale by BG since it earlier this year announced plans to look at asset sales across the globe to monetize some of its investments and return cash to shareholders.

APA Group is Australia's largest natural gas infrastructure business and following the acquisition of the QCLNG pipeline, will own and/or operate around A$19 billion of energy assets.