The head of the Marie Stopes clinic, which carries out non-surgical abortions in Northern Ireland, has confirmed that it has given its staff specialist training to cope with anti-abortion campaigners protesting outside its Belfast headquarters.

Volunteers escorting women into the clinic on Belfast's Great Victoria Street are having to wear cameras on their bodies to film the protests from the anti-abortion activists, according to its director Dawn Purvis.

She said many women in distress due to crisis pregnancies felt intimidated by the presence of anti-abortion militants.

"The women that come to us are very upset and very frightened by the behaviour of the protesters," Purvis said, adding: "The body-worn CCTV is for protection and public safety, and also to record potential incidents of criminal behaviour."

Anti-abortion groups insist their weekly protests are peaceful and their supporters in the Northern Ireland assembly have criticised Purvis and her staff's decision to deploy new security measures.

A Democratic Unionist party assembly member, Jim Wells, said: "I have spoken to some of the protesters and they do try to talk to women and persuade them not to have an abortion, but certainly, watching what goes on I don't see anything that would cause me concern.

"I would know most of the protesters and I don't think anyone needs a bodyguard.

"It's entirely verbal, and they have a right to persuade women not to have an abortion."

Anti-abortion groups have picketed the Marie Stopes clinic every week since it opened in October 2012. Women can access medication at the clinic to end pregnancies up to nine weeks of gestation only. Staff in the clinic also give women advice about later-term abortions in hospitals across the Irish Sea.

Northern Ireland is the only part of the UK where the 1967 Abortion Act does not apply and has resulted in thousands of women from there travelling to Britain and elsewhere in Europe for terminations.