By Scott Murdoch and Lewis Jackson

SYDNEY (Reuters) - Australia's Woodside Energy and rival Santos are unlikely to announce any agreement on a proposed A$80 billion ($52 billion) tie-up to create a global oil and gas giant until at least February, said a person with direct knowledge of the talks.

Woodside and Santos last week confirmed speculation they were in preliminary discussions to create a joint entity that would have assets stretching from Australia to Alaska, the Gulf of Mexico, Papua New Guinea, Senegal and Trinidad and Tobago.

Bankers are currently getting data and details on both companies, and work on a potential deal has only just started, the person said on condition of anonymity because the talks are private.

There is no fixed due diligence period or timetable at the moment, the person added.

Many Australians take holidays in December and January, the peak of the southern hemisphere summer, making it harder to complete transactions during the period.

Santos is being advised on the deal by Citigroup and Goldman Sachs, while Morgan Stanley is advising Woodside, sources confirmed.

Santos, Woodside and Goldman Sachs declined to comment, while the other banks did not immediately respond to requests for comment.

A second person with direct knowledge of the talks said only about 5% of the progress needed has been made so far, and Woodside has been driving the talks between both companies.

Woodside's first approach to Santos was made shortly after Santos' investor day on Nov. 22, the first person said.

Perth-based Woodside, the larger of the two companies, has said the talks with Adelaide-based Santos were confidential and there was no certainty an agreement would materialise. Its market capitalisation stands at A$56.91 billion, while Santos is valued at A$22.1 billion.

In an end-of-year video message to staff on Wednesday, Santos CEO Kevin Gallagher said Woodside had approached his company "a number of times" over the past year or so about a deal, according to a company source who confirmed comments first reported by the Australian Financial Review.