Barbadian Lisle Austin was appointed interim president of the North and Central America and Caribbean regional governing body on Monday in place of the suspended FIFA vice-president Jack Warner.
Austin's first act was to issue Blazer with a written demand to stop working with the U.S. lawyers, Collins and Collins, who presented evidence against Warner.
But Blazer, also a FIFA executive committee member, told Reuters on Tuesday that he had no intention of ending the relationship with the Chicago-based firm.
It was Blazer's report to FIFA's Ethics Committee, which included allegations of bribery against Warner and Asian football chief Mohammed Bin Hammam of Qatar, that led to this week's explosion of accusations and counter-accusations at world football's governing body in Zurich.
Austin gave the American 48 hours to explain by what authority he appointed Chicago-based Collins and Collins to conduct investigations into the members of CONCACAF.
Blazer said it was within his rights to work with the legal firm.
"It clearly falls under my jurisdiction as general secretary of CONCACAF," said Blazer.
The clash comes just days before CONCACAF's premier tournament - the Gold Cup - kicks off in Dallas on Sunday with the region's top national teams in action.
As well as the rift over the lawyers, Blazer moved on Tuesday to report his former long-time ally Warner to FIFA for breach of his suspension which bars him from all football-related activities.
