The G20 group of top world economies on Saturday said that global economic expansion was slower than had been expected but expressed confidence that a recovery would gain momentum.

"Global growth falls short of our expectations. We have pledged to take decisive action to keep the economic recovery on track and we are confident the global economic recovery will gain speed," finance ministers and central bank chiefs said in a draft communique after their two meeting in Ankara.

The economic supremos also vowed to "refrain from competitive devaluations and resist all forms of protectionism", following controversy over China's unexpected devaluation of the yuan last month.