A Saudi activist, who questioned the normalisation of ties between Saudi Arabia and Israel, has been detained in her home country, and could face up to five years in prison, a UK-based rights group said.

Noha al-Balawi has reportedly been under detention in the northwestern region of Tabuk for more than two weeks, ALQST, a group advocating for human rights in Saudi Arabia, said on Thursday.

According to ALQST, al-Balawi was asked to report to a police station in Tabuk on January 23, only to be arrested, and has been detained ever since.

Authorities reportedly questioned al-Balawi about her social media activities, including posts questioning the normalisation of ties between her country and Israel, the rights group said.

In one video clip widely circulated on social media, Balawi declared, "Normalisation means accepting the occupation", in reference to Israel's continued control of Palestinian land.

"Let me make it clear; we will never recognise Israel no matter what it will cost us.

"There is not a single benefit for Arabs when we normalise relations with Israel. It only serves the best interests of the Zionist state," she added.

In recent months, relations between Saudi Arabia and Israel have warmed up, with a flurry of diplomatic activities between Riyadh and Tel Aviv.

ALQST said that al-Balawi was also questioned for calling on the state to allow women to drive. In September 2017, the government of Saudi Arabia had already announced that it would allow women to drive starting in June 2018.

According to the report, the investigating officer had referred al-Balawi's case for trial under the country's cybercrime law.

Article 6 of the law states that a person "who creates or transmits anything prejudicial to public order" could face up to five years in jail, and/or a fine of up to $800,000.

ALQST said Saudi authorities are trying to mislead the public by denying al-Balawi's detention.

Earlier, ALQST said Saudi authorities had promised to release al-Balawi after five days. Instead, they have kept her for the past 18 days.

The group said al-Balawi's detention is an "obvious attempt" to silence public opinion.

'Outlandish punishments'

ALQST said al-Balawi's activism "is legitimate civil and human rights work", and that authorities "have no right to arrest, detain or punish her for such activity".

It is calling for al-Balawi's "immediate and unconditional release", and for authorities to "restore" her social media presence and allow her to express her opinions.

It remains unclear if and when al-Balawi will be tried in court, and which court will take up her case.

On Thursday, Saudi journalist Saleh al-Shehi was sentenced by a special criminal court to five years in prison.

The al-Watan columnist was accused of "insulting the royal court" after he discussed corruption and the royal court during a television appearance in early January.

"The emerging leadership's promise of openness and reform in Saudi Arabia seem to end where critical reporting and independent journalism begin," Sherif Mansour, Middle East and North Africa Program Coordinator of the Committee to Protect Journalists, said on Thursday following the conviction.

According to Human Rights Watch, since 2014, Saudi authorities have tried a series of peaceful dissidents in the Specialized Criminal Court, Saudi Arabia's "terrorism" tribunal.

There are at least over a dozen Saudi dissidents currently serving long prison terms based on their "peaceful activism", according to HRW.

"Outlandish sentences against peaceful activists and dissidents demonstrate Saudi Arabia’s complete intolerance toward citizens who speak out for human rights and reform," Sarah Leah Whitson, HRW Middle East director, said in January following the conviction of two human rights activists.