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''.
At the committee Mr Marshall said he "absolutely'' supported Mr Bush's attendance at the funeral and his eulogy, saying "you have to remember this was a funeral service attended by grieving family, by grieving friends and associates of the deceased and he made those comments in the context of that particular set of circumstances''.
Police Minister Anne Tolley had previously said Mr Bush's comment about Mr Hutton's integrity was quoted from his police record. Mr Mallard disputed this.
Ms Tolley tried to have Mr Mallard's questions on the subject ruled out of order because the Labour MP appeared to say Mr Bush should be sacked.
Mr Goff argued with National MP Jacqui Dean and swore after his questions about police redundancies and station closures were stifled.
Ms Dean said both outbursts were unacceptable.
Speaker David Carter will determine if there's a case to answer before the matter goes any further.
While Mr Goff was more forthcoming in admitting his behaviour wasn't ideal, Mr Mallard has refuted allegations his behaviour was inappropriate.
When asked if his behaviour at the committee was acceptable he said: "yes''.
He would not comment on the complaint made by Ms Dean, and said he did not threaten Mr Bush's job.
"Anyone who looks at it carefully will see that there was a debate as to whether questions around police salaries were in order and anyone who can read the estimates can see that's what we were being asked to approve."