The Scottish Parliament’s Standards Committee announced that the complaint would be referred to the Commissioner for Ethical Standards in Public Life for investigation.
The step was announced in a statement which also said MSPs on the Standards, Procedures and Public Appointments Committee believed there should be a “more robust process” for dealing with sexual harassment.
A SNP investigation into Mr McDonald has already found that the Aberdeen Donside MSP sent inappropriate and unwanted text and social media messages to women. The party investigation is also said to have found that he caused distress to women through unwanted attention and exploitation of his position of power.
A summary of the inquiry said there had been “persistent behaviour over an extended period of time”.
Before Mr McDonald returned to Holyrood after a four month spell away from the Scottish Parliament, the SNP MSP James Dornan wrote to the Standards Committee to lodge a complaint.
Mr Dornan said Mr McDonald’s presence at the parliament would be a “clear negation” of its duty of care to staff, arguing that he should not be in the same workplace as his victims.
The statement, read by committee convener Clare Haughey MSP, said: “Under the Commissioner’s Act, the Committee may refer certain complaints to the Commissioner for Ethical Standards in Public Life for investigation. Broadly speaking, the role of the Commissioner is to independently establish the facts of a complaint. The Committee will then consider whether it agrees with the Commissioner’s findings and any question of sanctions.
“We believe this is the most appropriate way of handling this complaint. The Commissioner is resourced to carry out this type of investigatory work, although we appreciate the sensitivities associated with this unique area. We do not think it would be appropriate for the Committee to undertake its own investigation and there is no procedure or precedent for the Committee to do so.
“We understand that due process must be followed and this will take time regardless of who carries out the investigation. It is in no one’s interest that this process becomes drawn out. We are confident the Commissioner will recognise this.”
She added: “We have therefore agreed today that we will issue a direction to the Ethical Standards Commissioner to conduct an investigation into this complaint.”
Ms Haughey’s statement went on remind MSPs that parliamentary rules stated that members should not discuss complaints or the intention to make a complaint with the press before lodging it.
Earlier she said the committee was conducting an inquiry into whether the MSP Code of Conduct is fit for purpose when dealing with complaints about sexual harassment and inappropriate conduct.
“There is still some way to go with our inquiry, but there appears to be an early consensus that a more robust process is required,” she said.
“There needs to be recognition of the sensitivities required when handling such cases and for there to be fairness to everyone concerned.And any new process will also have to try to reconcile openness and transparency, with privacy and a duty of care towards potentially vulnerable people.”