Cape Town - Deputy President Cyril Ramaphosa was booed by opposition MPs as he repeated government's rationale for granting Zimbabwe's first lady Grace Mugabe diplomatic immunity.Inkatha Freedom Party MP Liesl van der Merwe put Ramaphosa on the spot during a question session in Parliament, asking his opinion on what the decision will mean for gender violence and gender relations in the country.Mugabe was accused of beating 20-year old South African model, Gabriella Engels, on August 13 at a Johannesburg hotel where her two sons were staying.Also read: Grace Mugabe: diplomatic immunity isn’t an ‘out of jail’ ticket Ramaphosa said, by his understanding, the decision was taken in line with "internationally-recognised immunity regulations"."These regulations and conventions are understood and well recognised at a United Nations level, and that was utilised for this purpose," he said on Wednesday over the groans and objections coming from opposition benches."So clearly, it has its own sub-regulation in terms of its own efficacy. It's the first time we have utilised this type of convention."A lot can be said pro and against it."The groans grew louder from Economic Freedom Fighters and Democratic Alliance MPs at this point."Order, honourable members," National Assembly Speaker Baleka Mbete interjected."In the end, the clarity that we need on this matter is not full and complete. Yes, in certain environments it is applied, in others, it's not applied," Ramaphosa continued.'A very painful exercise'It was decided it applied in Mugabe's case, and that was why she was allowed to leave the country, he finished.The International Relations and Co-operation portfolio committee on Wednesday resolved to call in Nkoana-Mashabane to account for the events that led to Mugabe leaving the country. The committee held a workshop on Wednesday with department officials to discuss this term's agenda, where it resolved unanimously that Nkoana-Mashabane will be asked to appear following opposition requests.Read more: Parliamentary committee to call in Nkoana-Mashabane over Grace MugabeMeanwhile, Nkoana-Mashabane on Wednesday said granting Mugabe diplomatic immunity was painful."I am here. My name is Maite Nkoana-Mashabane. [I am] a very responsible mother, you can ask my children. Others know I am very supportive. It’s been a very painful exercise. It still is. Having said that, we are following the law," she told reporters in Pretoria.She said she had written to Mbete and the chair of Parliament’s international relations portfolio committee, Siphosezwe Masango, to report on the matter.A date must still be set for the minister to appear before the committee.Mugabe was accused of beating Engels with an extension cord.Engels said she sustained deep cuts to her forehead and the back of her head. She registered a case with the police the next day, alleging assault with intent to do grievous bodily harm.Mugabe returned to her home country on Sunday morning.