Labour MP Phil Goff has admitted swearing under his breath in a Parliamentary committee was inappropriate.
He said it was "never appropriate'' and "something I should never have done''.
A privileges complaint was laid last week with the Speaker of Parliament over Mr Goff's swearing and the behaviour of Labour MP Trevor Mallard during the appearance of Police Commissioner Peter Marshall and Deputy Commissioner Mike Bush at the Law and Order Select Committee.
Mr Mallard stormed out of the committee during a fiery exchange about the eulogy given by Mr Bush at the funeral of former detective inspector Bruce Hutton in April.
Mr Bush told mourners that Mr Hutton, who was found to have planted evidence in the Crewe murder inquiry, had: "integrity beyond reproach''.