Low oil prices normally help grease the wheels of business and spur global economic growth, but Moody's said it would not revise its forecasts for the G20,.
International Monetary Fund chief Christine Lagarde urged the Group of 20 major economies to fulfill their pledges to revive the faltering global economy.
Most of the world's powerhouse leaders arriving in Brisbane for the G20 summit to relax at their luxury hotels, but not Angela Merkel who opted for the pub.
President Barack Obama said the United States cannot "carry the world economy on our back" and urged G20 leaders to work harder to create jobs by revving up growth.
The fall in oil prices to their lowest levels in more than three years should give a boost to the sagging world economy, the International Monetary Fund said.
Finance chiefs of the Group of 20 economic powers said they remained confident about the global economy, despite renewed weakness in areas like the eurozone.
Switzerland has claimed the top spot on the Global Innovation Index for the fourth-straight year while Sub-Saharan Africa "posted significant regional improvement".
Reforms proposed to lift global growth in line with a target set by the world's biggest economies earlier this year are so far falling short, Australian Treasurer Joe Hockey said.
She might be one of the most powerful women in the world but that didn't wash with security at the G20 in Sydney who reportedly asked Janet Yellen to show her ID.
The OECD Friday said the winding down of US monetary stimulus should be a "wake-up call" for emerging economies to accelerate reforms, but Indonesia and South Africa stepped up criticism of the Federal Reserve heading into G20 talks.