A spokesman for David Johnston says he won't be there because the gathering is a working meeting with government on public policy issues.
Aboriginal leaders — most notably Attawapiskat Chief Theresa Spence — had been seeking a meeting with the prime minister and the Governor General in a bid to restart talks on full implementation of the treaty relationship.
Harper agreed and set Friday as the date for the meeting.
The Governor General was seen as an important participant for the meeting because he represents the British Crown, which negotiated the original treaties with aboriginal people.
Aboriginal chiefs are meeting in Ottawa this week ahead of Friday's talks, which are expected to focus on economic development and governance.
Spence, who has been on a liquids-only diet for nearly a month in an effort to secure the meeting, is also expected to attend.
Also on HuffPost