"We are now in a go period after two years of stop, or at least of very slow progress," Lamy said at a meeting of agriculture ministers in Berlin.
"The political context is more committed, more favourable," he said, adding, "it can be done."
Launched 10 years ago in the Qatari capital, the Doha Round of negotiations between the WTO's 153 member nations or trade blocs has repeatedly stumbled on trenchant disagreements and missed deadlines.
The last major push for a deal was launched in July 2008, but the initiative collapsed as developing and industrialised nations failed to agree on lowering tariffs on industrial goods and cutting subsidies on agricultural products.
The United States and Europe were accused by many developing nations of scuppering the deal by failing to adequately scrap subsidies for their farm sectors.
But Lamy said the agricultural chapter was 90 percent concluded, adding that the problems lay rather in other fields.
"But since everything is linked, we must settle these other fields."
European Union Agriculture Commissioner Dacian Ciolos said participants should not let bilateral agreements stand in the way of a global accord.
"We must make sure that we really get to the end of the round," he said.
Lamy said in mid-December that the "final countdown" had begun for the talks, noting that there was new energy to wind up the Doha Round in 2011.
At the same time EU Trade Commissioner Karel De Gucht said it had "become clear" that the United States wants to conclude the round.