TORONTO, Feb 15 (Reuters) - Canada's largest insurer Manulife Financial Corp on Thursday extended its goal to account Asia unit for half of its core earnings by 2025 by 2 years, citing the pandemic and a change in accounting method.

Manulife set the earnings target for Asia, which in 2023 brought about 23% the group's overall core earnings, in 2021.

Since then, the region has seen challenges arise as China's economy slows and the COVID recovery varied across regions.

Asia, where Manulife operates in 13 markets with about 13 million customers, has been a strong point for the company's earnings largely benefiting from a resurgence in mainland Chinese tourists returning to Hong Kong after pandemic restrictions were lifted.

"The recovery from the pandemic has been uneven across Asia. There have been some markets that have grown and we've seen improved momentum in some key markets," the unit's head Phil Witherington told analysts.

The insurer beat core earnings estimates for the fourth quarter powered by strength at its Asia and Canada businesses.

(Reporting by Nivedita Balu in Toronto and Jaiveer Shekhawat in Bengaluru, Editing by Franklin Paul)