"Canadians are not divided on their opposition to the status quo — that is to an unelected, unaccountable Senate," Harper said.
"The government is not going to take any actions going forward that would do anything to further entrench that unelected, unaccountable senate."
But while Harper said his intention is to "formalize" the moratorium on new appointments, he later said that it's not possible under the Constitution.
"I can't formalize a non-appointment. That would be a constitutional change. But under the Constitution of the day, the prime minister has the authority to appoint or not appoint," Harper said.
Harper said the benefit is that costs are down $6 million with 22 seats now unfilled: one fifth of the 105-seat chamber. He said the provinces have so far been "resistant" to reform.
Harper said the policy will remain in place as long as the government can pass its legislation.
Of the 22 existing vacancies, 15 belong to Ontario and Quebec. The two provinces combined are allotted 48 seats, something that has long frustrated westerners, with British Columbia and Alberta getting only six seats each.
The Conservatives have 47 seats, more than half of those that are filled. The Liberals have 29, with seven senators sitting as independents.
Harper has long struggled with the Senate on a number of fronts: as a Reform Party MP, he argued against having an unelected Senate. Once he took office as prime minister and faced with a minority government in 2008, he named 18 senators, including three whose expenses have since been investigated by the RCMP (two face criminal charges resulting from those probes).
Since the Senate scandal broke, Harper has avoided naming anyone new to fill the growing number of vacancies.