Dual citizen’s Guyana passport refused at Brickdam’s NIS office

Dear Editor,

I have dual citizenship and as such passports for both Canada and Guyana.  As a Canadian citizen, I would normally have my N.I.S. certificate authenticated by the Guyana Consulate in Toronto, but when I am in Guyana I would go at the N.I.S. office, Brickdam. At Brickdam however, for purpose of identification, they insist on providing your Canadian passport because you are residing overseas and refuse to accept your Guyana passport. Can N.I.S. say what is the rationale for such a decision and why a Guyana passport is not acceptable for purpose of identification?

Sincerely,
(Name and Address Provided)