New Zealand women who wear a headscarf in solidarity with Muslim women have faced a backlash from campaigners who say it is not 'empowering'.

Some women including Prime Minister Jacinda Ardern have covered up in the wake of the Christchurch mosque shootings which killed 50 people on March 15.

Ardern won widespread praise for putting on a headscarf when she met members of the Muslim community after the terror attack.

But women's rights advocates said it was a sensitive issue for many women who campaign against the obligatory wearing of headscarves.

New Zealand's Prime Minister, Jacinda Ardern, wears a headscarf at a gathering for Friday prayers in Christchurch on March 22

Critics pointed out that women in conservative Muslim countries such as Iran and Saudi Arabia were forced to cover up for the sake of modesty or risk public rebuke, fines or arrest.

'When we see non-Muslim women wear the hijab in solidarity of Muslim women it is very ironic and contradictory because our experience with the hijab is not empowering or uplifting in the political sense,' said Maryam Lee, a Muslim women's rights advocate and author in Malaysia who chooses to not wear a hijab.

'I wish [Ardern] hadn't but I understand where she is coming from because she is not a Muslim and not from a Muslim majority country.'

Women across New Zealand donned headscarves last Friday as part of a Head Scarf for Harmony campaign.

It was started by a doctor who heard about a woman too scared to go out as she felt her headscarf would make her a target for terrorism.

Lee, who has written a book called 'Unveiling Choice' about the hijab, said women in Malaysia opting not to wear headscarves would now receive more harassment and pressure to wear the hijab by Muslims citing Ardern's actions.

Women in Muslim-majority Malaysia, which has a large population of ethnic and religious minorities, have been barred from government offices in the past for attire that officials deemed as indecent, such as skirts or shorts.

Mourners offer funeral prayers for Syed Areeb Ahmed, a Pakistani victim of the Al Noor Mosque attack in New Zealand, at his funeral on March 25

Masih Alinejad, an Iranian activist and journalist who hosts the website My Stealthy Freedom where women in Iran post photos without headscarves, had mixed feelings about the campaign.

Alinejad has lived in self-imposed exile since 2009 and received death threats for her campaigning against the obligatory wearing of headscarves.

'I felt admiration that a prominent leader and women in New Zealand showed compassion to the Muslim community, but I also felt that you are using one of the most visible symbols of oppression for Muslim women in many countries for solidarity, and it also broke my heart,' said Alinejad.

'That is why I call on them to show their sisterhood and solidarity with us, who are being beaten up, imprisoned and punished for fighting against compulsory hijab as well.'

But Mutiara Ika Pratiwi, national secretary of Indonesian women's rights group Perempuan Mahardhika backed Ardern.

'Giving sympathy to a victim's family is part of a feminist position, and the veil is a symbol for a community that is currently a victim,' said Jakarta-based Pratiwi.

'Although there are those who criticize her, the majority respect the move. What is important is that Jacinda is able to build a movement of New Zealanders who sympathize with the victims.'