Shell announced yesterday that the Chinese Ministry of Commerce had approved its proposed marriage with BG - the final pre-conditional approval needed for the combination.

The Australian Foreign Investment Review Board approved the merger last month after the Australian Competition and Consumer Commission gave its own unconditional approval of the combination on November 19 having delayed its decision, voicing concerns over competition impacts on the local gas market.

Shell CEO Ben van Beurden said the addition of BG's integrated gas assets in Australia to Shell's global portfolio was "one of the main strategic drivers" behind the recommended combination.

"The Shell-BG combination is a sign of Shell's confidence in the Australian economy," he said.

"It is also a springboard to change Shell into a simpler, more profitable and resilient company."

With approvals now in place from Australia, the European Union, China and Brazil, a merger prospectus will be sent to shareholders, with both BG and Shell to hold special general meetings to get their respective shareholders' approval.

This won't be complete smooth sailing, however, as some have voiced doubts about the merger's merits, particularly given the continued drop in oil prices.

In fact, Reuters says the deal's value has now dropped from $US70 billion ($A95.5 billion) to $53 billon due to the fall in Shell's share price since April 8 when the deal was first announced.

"We're grateful to MOFCOM for its thorough and professional review of the recommended combination, and I am delighted we now have all the pre-conditional approvals needed to move to the next important phase," Shell CEO Ben van Beurden said.

"This is a strategic deal that will make Shell a more profitable and resilient company in a world where oil and gas prices could remain lower for some time. We will now seek approval from both sets of shareholders as we move towards deal completion in early 2016."

Shell also announced yesterday that it expects an overall potential reduction of about 2800 roles globally across the combined group, which constitutes about 3% of the total combined group workforce.

These are in addition to the previously announced plans to reduce Shell's headcount and contractor positions by 7500 globally.

"Shell's expectation is that BG's business would be integrated into Shell's businesses," the UK super-major said.

"As part of that, Shell proposes that office consolidation will be undertaken where practical in certain locations around the world.

"With regards to office footprint rationalisation in the UK, Shell will, following deal completion, undertake a comprehensive review during the course of 2016."

Shell re-iterated that the deal is still on track for completion early next year.