Federal Human Services Minister Michael Keenan will not contest the next election, making him the second minister to quit ahead of the federal poll.

Key points: Mr Keenan is leaving politics after 15 years as member for the WA seat of Stirling

Mr Keenan is leaving politics after 15 years as member for the WA seat of Stirling He has cited family reasons, saying he cannot commit to another term

He has cited family reasons, saying he cannot commit to another term He is the second high-profile departure —fellow Minister Kelly O'Dwyer is also quitting

It is understood Mr Keenan wants to spend more time with his family.

He was elected as the member for the WA electorate of Stirling in 2004.

Mr Keenan was one of a slew of ministers who quit former prime minister Malcolm Turnbull's cabinet ahead of the leadership spill in August 2018.

"Whilst politics is a proud vocation, it is also difficult and exhausting business," Mr Keenan said in a statement.

"The pressures on family life are formidable, as are the constant rigours of being an effective Member of Parliament, as well as a Minister in the Government," he said.

"I have always worked hard as a Member of Parliament and as a Minister, but after doing this for 15 years, I cannot commit to another term.

"Over the Christmas break, it became very clear to me personally that times have changed and that this decision was the right one for my family and myself."

Mr Keenan holds his electorate of Stirling by a margin of 6.1 per cent.

He served as justice minister and later human services minister under Malcolm Turnbull.

The West Australian held on to the human services portfolio after the leadership spill, but the role was shifted out of Cabinet.

Keenan's resignation follows O'Dwyer's exit last week

Mr Keenan is the second high-profile departure from the Morrison Government ahead of the election, which the Prime Minister said will be in May.

He follows Minister for Jobs and Women, Kelly O'Dwyer, who announced she would not recontest her Melbourne seat of Higgins.

Ms O'Dwyer also cited her family as the main driver for her departure, saying she wanted an opportunity to have another child.

She has been accused of deserting the Government ahead of a tough election, a claim she and the Prime Minister have strenuously denied.

Ms O'Dwyer said she would not contest the next election for "very personal" reasons. ( ABC News: Nicole Asher )

The Liberals are concerned about their electoral fortunes in WA, despite being able to campaign on changing the GST carve-up to ensure the state receives more tax revenue.

Fellow West Australian Liberal Mathias Cormann was quick to pay tribute to his colleague.

"Serving in the Federal Parliament at such a senior level from WA is tough on our families," he said in a statement.

"Michael had no kids when he first got elected back in 2004.

"Today he and Georgina have four beautiful boys.

"We are sad to see him go, but entirely understand and respect the reasons for his decision."

Member for Stirling's departure 'surprising': analyst

WA-based political analyst William Bowe said Mr Keenan's decision was a significant blow to the Coalition.

"It greatly reduces the odds of the Liberal Party holding onto Stirling," Mr Bowe said.

"And it's just never what you want to happen … to lose a sitting member with the advantages that you have in being an incumbent in a seat that could go either way.