The SNP has suspended Mark McDonald after a fresh allegation was made to the party.
The 37-year-old resigned as a government minister earlier this month following a complaint to the party over a text message he had sent in the past.
The MSP, who represents Aberdeen Donside at Holyrood, will now sit as an independent member while the party investigate the latest allegation.
A party spokesman said: "Following new information being received by the SNP over the course of the last 24 hours relating to the behaviour of Mark McDonald, he has been suspended from both the parliamentary group and the party while further investigation takes place.
"In the interests of due process and appropriate confidentiality no further comment will be made."
McDonald said: "I have not been advised of any details relating to the information received by the party but I stand ready to fully cooperate with any investigation into this matter.
"I will make no further comment at this time and would ask that due process be allowed to take its course and that the privacy of my staff and my family is respected and that they be allowed to go about their daily lives without obstruction."
He has previously said he is "determined" to change his behaviour.