* Unit to hold supervisory board meeting Monday-source
* Unit CEO flagged cost cuts in December
* Lufthansa took full control of Brussels Airlines in 2016 (Adds quote from source, context on Brussels Airlines)
BRUSSELS, Feb 4 (Reuters) - German airline Lufthansa wants to replace top management at Brussels Airlines, a person familiar with the matter told Reuters on Sunday, pointing to the unit's weak performance compared to other divisions.
The changes, which would affect Brussels Airlines' chief executive and chief financial officer, will be discussed at a supervisory board meeting of the unit scheduled for Monday, the person said.
"If you want to improve Brussels Airlines it can only work with a new management," the source said.
Lufthansa declined to comment.
Brussels Airlines plans to cut its costs by between 10 and 15 percent in the coming years to remain competitive with low-cost rivals, its Chief Executive Bernard Gustin told Belgian daily De Tijd in December.
Lufthansa took full control of Brussels Airlines in late 2016, expanding its network in Africa, where the Belgian unit flies to many sub-Saharan destinations. Currently, Brussels Airlines has 44 planes, 10 of which are long-haul jets. (Reporting by Peter Maushagen; writing by Christoph Steitz; editing by Jason Neely and Adrian Croft)