Prime Minister Stephen Harper is expected to name eight new members to the Senate as early as Thursday, and the appointments will include loyal and long-serving Conservative advisers, CBC News has learned.

Sources in Ottawa have told CBC News that new senators will include Doug Finley, the main strategist for the Conservatives through four general elections, and Carolyn Stewart-Olsen, a senior adviser to Harper for about seven years.

Don Plett, the current president of the Conservative party, may also accept an appointment.

The moves will mark the second round of appointments Harper has made to the upper house in less than a year. In December, Harper named 18 new senators, including former broadcaster Pamela Wallin, Olympic icon Nancy Greene Raine and CTV broadcaster Mike Duffy.

When the eight new senators are named, the appointments will give the Conservatives 46 of the 105 seats in the Senate. The Liberals have 53. The rest are independent.