Asked about the division of burdens amongst NATO members in the country, MacKay said in an interview with German news website Spiegel Online that German troops need to join the other countries fighting in the embattled south.
"Just look at what countries are there or were there: The Romanians, the Estonians and the Danes. These are countries that arguably have less military capacity than Germany," said MacKay, who also told the website that France, Spain and Italian should send troops to the south.
More than 80 Canadian soldiers have been killed fighting in Afghanistan.
"I don't think of Germans as quitters by any stretch. Their contribution in Afghanistan is very valuable. However, our roles are different," MacKay said. "Germany's presence there actually outnumbers Canada's. But they are based primarily in the north, near Kabul, while we are based in the south - in Kandahar, where some of the heaviest fighting in Afghanistan is going on."
Southern Afghanistan, with the highest concentration of opium production and Taliban fighters, is the most dangerous region in the country. According to the United Nations, unrest there killed 8,000 people in the last year.
Meanwhile politicians in Berlin are calling on Chancellor Angela Merkel to address a timeline for the withdrawal of German troops from Afghanistan, and she has pledged not to cave to US and international pressure to expand Germany's presence there.