Shawn Brant's lawyer, Peter Rosenthal, speaks to the media on Saturday. (CBC)

The Ontario Provincial Police commissioner should be suspended while an investigation is launched into comments he made during a First Nations blockade last year, the lawyer for the man who led the protest says.

Peter Rosenthal, who represents Mohawk protest leader Shawn Brant, is calling for a government investigation into comments Commissioner Julian Fantino made to Brant in a telephone conversation during an aboriginal day of action last year.

"In my view, what should be done right now is, Premier [Dalton] McGuinty should direct some people within his government to seriously consider what Commissioner Fantino said under oath at the preliminary inquiry as posted on the CBC website and then consider whether or not it's appropriate for Mr. Fantino to remain commissioner of the OPP," Rosenthal told a news conference on Saturday.

Newly released court documents show the OPP were just minutes away from moving in to forcibly remove a First Nations blockade that prompted the closure of Highway 401 during the aboriginal day of action last summer.

The documents include wiretap transcripts that feature Fantino telling Brant in a telephone conversation that "your whole world’s going to come crashing down" and threatening to "do everything I can within your community and everywhere to destroy your reputation" during the tense standoff between police and aboriginal protesters at blockade sites in eastern Ontario.

Rosenthal said Fantino should step aside while the remarks are investigated.

"This is very crucial. A man was killed in 1995 by an OPP sniper. Commissioner Fantino admitted that … there were snipers ready at this time and he was close to moving in.

"Somebody could have gotten killed. Luckily nobody was killed or injured. This kind of attitude is going to lead again to another Ipperwash or at least has a high probability of doing so given the number of such protests that take place."

Rosenthal said the exchange contradicts the OPP's guidelines for dealing with aboriginal groups, a policy that was recommended in the wake of the police killing of Dudley George at Ipperwash Provincial Park in 1995.

Rosenthal also said the tap on Brant's cellphone was made without obtaining a court order. Rosenthal said while the Criminal Code allows for wiretaps without a court order in extreme situations, there was plenty of notice given about the day of action last year.

Fantino has not commented on the transcripts, but McGuinty said Friday that he stands by the commissioner.