John Hutton has told the BBC Europe "needs to do more" to provide troops in the toughest areas of Afghanistan.
Echoing US calls, the defence secretary said it was not fair the US was doing "all the heavy lifting".
Britain was already punching "above our weight" and had not been asked for more troops so it was for "others" to contribute more first, he said.
Speaking ahead of a Nato meeting in Poland, US Defence Secretary Robert Gates urged allies to increase troops.
US President Barack Obama said he would deploy an additional 17,000 US soldiers in Afghanistan - bringing total US troops in the country to more than 50,000.
Mr Hutton told BBC Radio 4's Today programme: "The ball is absolutely in Europe's court now and we need to pick it up if we are going to be seen to be responsible, effective allies of the US who are doing all the heavy lifting in Afghanistan."
He said the extra US troops would help improve security - which was crucial if progress was to be made on the political front and with reconstruction.
And he said it would "highlight" the controversy over Europe's contribution to the military effort in Afghanistan.
"Our view has always been very clear - that Nato needs to do more, the European members of Nato need to do more.
"There needs to be a a fairer burden sharing of responsibility, particularly in those really hard areas where what we need are combat forces."
He said there were 30,000 European troops in Afghanistan and Nato had begun to develop a clear response to the threat posed by "international jihadist extremists" - but needed to look at "what more we can do."
Asked if a troop shortage had hampered progress, he said: "I think that's probably right."