Asked by a Twitter user how Berlin state secretary Sawsan Chebli got her position, Efgani Dönmez tweeted over the weekend: "Look at her knees, maybe you find an answer there".
Chancellor Sebastian Kurz's People's Party (ÖVP) dismissed Dönmez, who ran on an ÖVP ticket during national elections last year, saying "sexist, offensive gaffes are not acceptable".
Dönmez -- facing calls to resign as a parliamentarian -- said he would continue in his position without party affiliation.
Dönmez removed the tweet, saying on Sunday he only meant to address Chebli's "attitude", supporting conservative Muslim groups, and not her "origins or gender". Chebli is the daughter of Palestinian refugees.
"Based on the discussions that have followed (my tweet) I see in hindsight that I have degraded Ms. Chebli. It was a moment of weakness, absolutely wrong of me, and I apologise for this sincerely to her and to all who have felt hurt
through this," Dönmez posted.
The ÖVP has been governing Austria since late last year in a coalition with the far-right FPÖ.