Marriott International on Monday made a roaring comeback in its battle to build the world's biggest hotel group, winning Starwood Hotels's green light for an improved bid and pushing Chinese rival Anbang to the sidelines.

Only days after Starwood dumped Marriott as a merger partner in favour of an Anbang-led consortium, Starwood's board endorsed a higher Marriott offer, both hotel companies said in a joint statement.

Starwood's board decided that the revised terms "constitute a superior proposal" to the Anbang bid.

The revised Marriott cash-and-stock bid values Starwood at $13.6 billion (12.1 billion euros), compared to $13.2 billion in Anbang's latest bid.

Marriott is offering 0.8 of its stock for each Starwood share plus $21 in cash per share.

"The companies have signed an amendment to their definitive merger agreement that creates the world's largest hotel company," they said.

Only on Friday, Starwood had announced that it favoured the Anbang-led bid over an earlier deal with Marriott.

But on Monday, the joint statement said that Marriott's revised bid "offers superior value for Starwood's shareholders, the ability to close quickly, and provides value creation potential that will allow both sets of shareholders to benefit from improved financial performance".

China's Anbang Insurance is on a shopping spree in the US hotel sector which includes the Starwood bid, but also the $6.5 billion purchase of 16 luxury properties from Blackstone.

Anbang made headlines in 2014 when it acquired the New York landmark Waldorf Astoria Hotel.

Starwood, the owner of the Westin and W brands among others, has some 1,270 properties in 100 countries.

Marriott has more than 4,400 properties in 87 countries and territories, with a portfolio of brands including The Ritz-Carlton, JW Marriott and Gaylord Hotels.

Marriott and Starwood said they had already cleared major regulatory hurdles for their tie-up, including pre-merger antitrust reviews in the US and Canada.

The deal also still requires approval from both hotel chains' shareholders.

Marriott and Starwood said they expect the deal to close by mid-2016.