The SNP’s former Westminster leader was told about Alex Salmond allegedly behaving with “inappropriateness” towards female Edinburgh Airport staff in 2009 but said he accepted the then-first minister’s denials.
Angus Robertson revealed a manager at the airport reported concerns to him but Mr Salmond insisted he had not acted inappropriately.
Mr Robertson suggested the “matter was resolved” after speaking to the airport manager again.
The former MP, who is standing as a candidate for the SNP in Edinburgh Central at next year’s Holyrood election, said no formal complaint was made about the incident.
The disclosure was made in a submission to the Holyrood inquiry looking at the Scottish Government’s botched handling of sexual harassment complaints about Mr Salmond.
But Mr Robertson does not state whether he ever told anyone else – either in the SNP or the Scottish Government – about the Edinburgh Airport allegations.
In a letter to the Committee on the Scottish Government Handling of Harassment Complaints, Mr Robertson said: “In 2009, I was called by an Edinburgh Airport manager about Alex Salmond’s perceived ‘inappropriateness’ towards female staff at the airport.
“I was asked if I could informally broach the subject with Mr Salmond to make him aware of this perception.
“I raised the matter directly with Mr Salmond, who denied he had acted inappropriately in any way.
“I communicated back to the Edinburgh Airport manager that a conversation had happened. The matter being resolved, and without a formal complaint having been made, it was not reported further.”
In November 2017, Sky News asked the Scottish Government about the claims by airport staff, which was then flagged with First Minister Nicola Sturgeon and her husband – the SNP’s chief executive Peter Murrell.
Both have said this was the first they heard of potential inappropriateness by Mr Salmond.
The former first minister was later acquitted by the High Court in Edinburgh of attempted rape and a series of sexual assaults, including one with intent to rape.
He earlier successfully challenged the Scottish Government’s investigation of sexual harassment claims, being awarded £512,250 after the Court of Session said it was unlawful and “tainted with apparent bias”.