The Philippines' National Bureau of Investigation (NBI) said the FBI, its US counterpart, had sought help in finding Marilou Danley.
"Danley arrived in the Philippines last month, and then there was a wire transfer to her account for $100,000 from Stephen," NBI spokesman Nick Suarez told AFP.
"The FBI has coordinated with the Philippine office of the Interpol to look for her."
Suarez said the FBI considered Danley a "person of interest", but not necessarily a suspect.
Paddock, a 64-year-old gambler and retired accountant, killed 58 people and injured at least 527 others when he used a vast arsenal of weapons to shoot at a Las Vegas concert from a hotel room on Sunday.
Suarez and other Filipino authorities would not say if Danley, 62, was still in the Philippines.
The US embassy referred questions on her whereabouts to the Philippine government.
"From the US side, we are not able to comment on ongoing investigations, and I would not want to get ahead of the authorities leading the investigation," US embassy spokeswoman Molly Koscina told AFP by email.
Danley is an Australian citizen who moved to the United States 20 years ago to work on the casino strip, the Australian government confirmed Tuesday.
"There are reports her ID was used for booking the hotel or some such detail," Australian Foreign Minister Julie Bishop said.
"Australia will support the US authorities in their investigation in whatever way we can, but we have not had contact with Marilou Danley directly."
Media reports said Danley was born in the Philippines, although the Philippine foreign department and Suarez said they could not confirm that.
Paddock killed himself after mowing down the concert-goers.
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