Nooryana Najwa Najib has criticised authorities for arresting her mother Rosmah Mansor, the wife of former premier Najib Abdul Razak.

"I can accept taking action on a man who was in power, but putting the women in his life in harm's way is going too far. Two weeks ago, you raided his mother's house, and today, you remand (sic) his wife, and plan on charging her the same day her husband is due in court.

"I suppose tomorrow makes for a great picture and media circus. The dreaded call came in at 4am. Too sad to cry, too angry to scream, I just got up, took wuduk (ablution) and prayed tahjud (night prayer) for Mummy," she said in an Instagram posting.

Nooryana, who is in the US, vowed to always stand by her mother no matter what.

Rosmah was arrested at 3.20pm at the MACC headquarters in Putrajaya this afternoon, after having arrived there about 11am to have her statement recorded.

She is expected to be slapped with several charges under the Anti-Money Laundering, Anti-Terrorism Financing and Proceeds of Unlawful Activities Act 2001 at the Kuala Lumpur Sessions Court tomorrow morning.

Najib is also due to appear at the KL High Court tomorrow pertaining to his previous money laundering and abuse of power charges.

On Sept 20, a team from Bukit Aman raided the home of Najib's mother, Rahah Mohammad Noah, in Jalan Eaton, Kuala Lumpur, upon receiving information that the former premier had stashed a substantial amount of cash there.

The team broke the ceiling of the house during the search but returned empty-handed.

'Please get some rest'

Meanwhile, Nooryana hoped that Rosmah would remain calm and composed as the latter would be worried about everyone at home.

"I know she's wondering - 'How’s Gina taking it? I hope she still goes to class today. Is Adam ok?'.

"Mummy, even if you can’t hear me, please know that I am fine. I will get out of bed and go to class and Adam will be patiently waiting for you on FaceTime. Please try to eat and get some rest tonight.

"No matter how hard the circumstances are, I will always stand by the woman who gave birth to me, wiped my tears away when I was down, slept with me when I was sick and taught me how to stand on my own two feet.

"In your words this morning mummy, Insya Allah, we will persevere," she wrote.

'Let the courts decide'

Meanwhile, in a separate Instagram posting, Rosmah's estranged daughter Azrene Soraya Abdul Aziz wrote that despite her reported feud with Rosmah, sympathy exists nonetheless, following the latter's arrest.

"May Allah make it easier. At the end of the day, what is right is right, what is wrong is wrong, it's up to the courts to decide now," she said.

Her husband - singer and celebrity chef Fazley Yaacob, uploaded the same words in his personal Instagram account.