Trevor Mallard's move to trespass Winston Peters from Parliament has cost the taxpayer more than $23,000 in legal fees.
The former speaker trespassed the former deputy prime minister after he visited the anti-mandate occupation in May.
An answer to a written parliamentary question from the National Party showed the legal fees totalled more than $23,000.
Charges for correspondence, meetings and preparing legal documents had totalled $23,585.45 to date, current speaker Adrian Rurawhe confirmed.
Rurawhe has apologised to Peters about the trespass notice, saying it was "unreasonable and irrational".