Wiktionary
a. Of or relating to a prime minister.
Usage examples of "prime ministerial".
Almost alone of all the guests in that vicinity they were taking no interest in the Prime Ministerial throng.
As he drew up in front of the prime ministerial office building, he glanced at his watch.
It would eliminate the prospect of going to jail at some future date, but pretty much ensure that prime ministerial wrath would descend on you with full force.
It was all very different from her usual Prime Ministerial visits, and oddly intimate--and she certainly didn't miss the usual scrum of journalists and assorted hangers-on.
So this meeting is in the nature of a judicial inquiry having Prime Ministerial status.
They get a lot of tourists running out of money and trying to get home, so tell them this is prime ministerial business and ask them to put you on the line to the Foreign Office in London.