After days of silence, Justice Minister Michael Keenan has taken to social media to say he renounced his British citizenship, which he inherited from his father, before entering Parliament in 2004.

Mr Keenan was the third Turnbull minister to come under the dual citizenship spotlight.

Despite two days of repeated questioning by Fairfax Media, Mr Keenan's office had refused to say when he had renounced his British citizenship, only maintaining that the minister is an "Australian citizen and does not hold citizenship of any other country".

Experts had warned that Mr Keenan could be a "citizen by descent" of Britain, unless he or or his father went through the formal renunciation process.