The Clerk of the Committee spoke to Smith as he sat in the front row of the public seating.
Parliament's Serjeant-at-Arms then entered and spoke to Smith, putting off economist Rodney Jones as he gave evidence.
Committee chairwoman Maggie Barry assured Jones, "we are paying attention".
She later told the committee the matter was in the hands of Speaker Trevor Mallard.
Mallard declined to comment today.
Smith told the Herald after the hearing that it was appropriate for him to attend the select committee hearing.
"I was attending as a member of the public and was not able to question or participate in the hearings."
"My reading of the Standing Orders is that my status for 24 hours, including not getting a pay cheque, is that I'm the same as a member of the public and exercised those rights."
Smith said he would be unconcerned if the Speaker became involved again. "It would be extraordinary for me not to sit in the public gallery and have no more rights than an average citizen."
The issue that precipitated Smith's expulsion from Parliament yesterday was his questioning of Police Minister Stuart Nash in relation to the death of Matthew Dow, 23, who was killed at Appleby near Nelson on New Years Eve in 2017 by a driver high on meth and cannabis.
Smith asked Nash if he stood by his statement to TVNZ last December when he had said a discussion document on roadside drug testing had been approved by Cabinet and would be made public early in 2019.
Nash said he did not recall making that statement on television - public records show he did say it – but work was being done in that area.
Today fellow National MP Chris Bishop continued that line of questioning to Deputy Prime Minister Winston Peters, answering on behalf of the absent Nash.
Peters confirmed Cabinet decided in September to undertake public consultation and the document is due to be released shortly.