Former South Australian Liberal Leader David Speirs is quitting politics after being charged with drug offences.

Speirs said on Saturday he would step down later in October, after police arrested him and raided his home.

SA Police later confirmed the 39-year-old was arrested at Berri on September 26 and charged with two counts of supplying a controlled substance between August 2 and 3 and on August 9.

“Following this his residential premises was subsequently searched,” they said.

Speirs was granted bail and will face court at a later date.

The police statement followed Speirs’ post on social media, which said he would formally step down as the member for Black, in Adelaide’s south, when parliament resumes on October 15.

“Since allegations of illicit substance use in my home became public, my home has been raided by armed police, I was arrested and I was questioned,” he said in a video.

Speirs said he did not believe he could “adequately and effectively serve my local community while also dealing with this matter, protecting my mental health and supporting my family and friends”.

He said he would suspend his Liberal Party membership and thanked his colleagues for their support.

“For me, it’s time to move on. I want to rebuild myself over the coming months and into the future,” Speirs said.

“I want to be a better son, I want to be a better friend; to be honest, I want to be a better person.

“That takes time, and I believe it’s best done away from public life.”

Speirs resigned as state opposition leader on August 8 and was replaced by Vincent Tarzia, who said on Saturday the party’s state executive had ratified the suspension of Speirs’ membership.

The party respected Speirs’ decision to quit, Tarzia said.

“It’s obviously a very hard, challenging decision for him,” he said.

“I know he hasn’t made that decision lightly.”

Standing down was in the interests of Speirs’ mental health and welfare, “but also in the interests of his community and the parliament”, Tarzia said.

He said the party would focus on preselecting “the best candidate we can” to hold the seat of Black, which Speirs has held since 2018.

-AAP