By Alasdair Pal

SYDNEY (Reuters) -The leader of Western Australia resigned on Monday in a surprise announcement, citing exhaustion, after guiding the resource-rich state through the COVID pandemic.

Premier Mark McGowan, elected in 2017, is a member of Australia's ruling Labor Party, which also holds a large majority in Western Australia. He will also step down from the state parliament this week, he told a news conference.

"I have loved the challenge of solving problems, making decisions, getting outcomes, and helping people. But the truth is I'm tired, extremely tired. In fact, I'm exhausted," McGowan said.

McGowan won a landslide re-election in 2021, with his COVID policies that effectively isolated the state from the rest of Australia proving wildly popular.

Labor now holds 53 of 59 seats in the state's lower house, and is widely expected to return to power in an election due by 2025.

"While it's true the sheer scale of his final election victory earned him a place in Australian political history, I know Mark's definition of success has always been about delivering for people, improving lives and creating progress that endures," Prime Minister Anthony Albanese said in a statement.

Western Australia is the country's largest state by area and is rich in resources including iron ore and natural gas.

Labor has not yet announced the process for replacing McGowan.

(Reporting by Alasdair Pal in Sydney; Editing by Lincoln Feast)