FRANKFURT (Reuters) - The insolvency administrator of Niki said he would press ahead with an agreed sale of the Austrian airline to British Airways owner IAG (>> International Consolidated Airlines Group), even as a German court ruling complicates Niki's insolvency process and puts the deal at risk.

A secondary insolvency filing in Austria, which Niki will submit by the end of this week, will safeguard the sale, Lucas Floether said in a statement on Tuesday.

Vueling, IAG's budget carrier that would absorb Niki under the planned deal, had already said on Monday it was still interested in Niki, the former Austrian unit of collapsed Air Berlin.

(Reporting by Maria Sheahan; Editing by Arno Schuetze)