Environmental activist Shariffa Sabrina Syed Akil's daughter cried injustice over her mother's arrest.

Sharifah Fareena Syed Yusof, 20, took to her Instagram to express her sadness and anger over the investigation against Shariffa.

Shariffa, who is a puan sri, had shared a screenshot of her daughter's posting on her Facebook page today.

"I am deeply saddened by what has happened to my mother," lamented Sharifah Fareena.

"This is injustice at its best (sic)," she said.

Shariffa, who is Pertubuhan Pelindung Khazanah Alam Malaysia (Peka) president was arrested on Dec 22 together with Peka administrative officer Norhayati Shahrom, for allegedly insulting the Johor sultan by posting on Facebook about logging on land belonging to the monarch.

They were being probed under Section 233(1)(a) of the Communications and Multimedia Act 1998 (CMA)

Section 233 of the CMA concerns improper use of network facilities or network services and provides for a fine up to RM50,000 or imprisonment up to a year or both.

"Somehow, people have made it seem like it is wrong to fight for what we truly believe in, and that it is wrong to fight for those who do not have a voice," said the daughter.

Malaysians are being oppressed and we are living in fear, she claimed.

"Freedom of speech and expression are not accepted and I witnessed it first hand," she said.

She said her mother was a fighter, who fought for something that no one dared or wanted to fight for.

"She is not only fighting for me and my family, but also for our future. She is fighting for all of you and most importantly, for nature," she said.

"She will continue to fight for what is right and we will stand by her, forever and always," she added.