Lwandamina has been in charge of Chipolopolo since he replaced Honor Janza after the Cosafa Cup in South Africa in May.
Zambia were recently knocked out of the African Nations Championship in the quarter-finals in Rwanda after a 5-4 loss against Guinea.
"I am happy for George, FAZ is happy with him at the front. He has matured and getting better all the time," Kalusha told Post Zambia.
"Ever since he took over, you can see a remarkable improvement with each game; he enjoys the fullest confidence of everyone. George will continue as coach of the national team for a long time. He deserves his chance, that's why I am saying don't worry."