Prime Minister Stephen Harper will shuffle his cabinet on Tuesday to fill a vacancy in the Environment portfolio, CTV News has learned.

The shuffle will include about five or six portfolios and will allow some new faces to enter into key government positions, Ottawa Bureau Chief Robert Fife reported late Monday.

Still, Fife said that the person tapped to become the new environment minister remains a closely guarded secret. There has been some speculation that current Heritage Minister James Moore will take over as environment minister, but that was not confirmed Monday.

However, Fife noted that Ontario MP Peter Kent, who is the minister of state for foreign affairs of the Americas, could be promoted to a full cabinet minister.

Fife added that Alberta MP Ted Menzies, who is the current parliamentary secretary to the finance minister, could also be given a full cabinet post.

Other ministers, according to Tory insiders, who may be given new assignments in cabinet include:

• Health Minister Leona Aglukkaq
• International Co-operation Minister Bev Oda
• Fisheries Minister Gail Shea

The Environment portfolio was vacated late last year by Jim Prentice, who has left the government to take a high-profile job as vice-chairman of CIBC.