The partner of the Sydney siege gunman has had her bail revoked after being deemed an "unacceptable risk" by a magistrate.

The Director of Public Prosecutions (DPP) had asked for Amirah Droudis's bail conditions to be reviewed following last week's siege at Martin Place.

The gunman, Man Haron Monis, and two hostages died when armed police stormed the Lindt cafe after a 16-hour standoff.

Droudis is charged with murdering Monis's ex-wife, Noleen Hayson Pal.

Ms Hayson Pal was stabbed multiple times and set alight at a western Sydney apartment block last year.

Monis had been on bail charged with being an accessory to murder.

The DPP argued Droudis's bail should be reviewed in light of new circumstances, which included the siege and videos posted online.

A number of videos posted by Droudis in 2009 allegedly echoed the teachings of Monis, including support for the Bali bombing and 9/11 attacks.

The prosecution said the videos were evidence of Droudis's willingness to act on Monis's behalf.

The DPP also said views expressed by Droudis in the videos were seen by many as extremist in nature and her views had not changed since they were recorded.

In court prosecutors admitted to "failings" when they opposed Droudis's bail in 2013, conceding that evidence proving her tendency to follow Monis's instructions was not put before the court.

But Droudis's legal team on Monday told the court the bail review was frivolous and argued it should be refused.

Chief Magistrate Graeme Henson adjourned the court twice so he and both legal teams could watch video evidence presented to the court.

"There is a need not to be overborne of emotion and that justice in a democratic society should be applied to all," Mr Henson said.

But after viewing the videos, Mr Henson determined they had nothing to do with the bail review.

The content of the videos cannot be reported for legal reasons.

Droudis was swarmed by media when she stepped out of a taxi to face Downing Centre Local Court in Sydney on Monday morning.

Wearing a white beanie and sunglasses, she said nothing to reporters and her stepbrother asked for them to be left alone.

After the magistrate announced his decision, Droudis was surrounded by security guards who took her personal belongings before she was taken into custody.

She was originally given bail in December 2013 after being charged with murder as a magistrate deemed the case against her to be weak.

It is alleged Droudis committed the murder at Monis's request.

NSW Premier Mike Baird issued a statement welcoming the decision to revoke Droudis's bail.

"The NSW Government expects community safety to be front and centre of all bail decisions and that is why the Attorney General expressed concern and requested a review of the case," he said.

"As the matter is before the courts I will be making no further comment."

Droudis is due to appear in court on February 22, 2015.