MELBOURNE - Protectionism is slowing the world economy and the upcoming Group of Twenty (G20) summit in China's Hangzhou needs to focus on international cooperation that enhances free trade between nations, a leading bank executive said.

Huang Xiaoguang, CEO of the Australia and New Zealand Banking Group (ANZ) in China, said the summit, which features leaders from the leading 20 economies, would focus on combatting slow economic growth.

"I think cooperation to tackle the global issues together will be the major agenda item," Huang told Xinhua at ANZ's global headquarters in Melbourne.

"Today (in) the world economy, for example, you see protectionism and that will slow down the world economy and create a lot of issues.

"I think G20, representing the most important countries in the world, should be in the position to work together to make our world better."

Huang praised China's Belt and Road Initiative, dubbed "the modern silk road" a great solution to counter sluggish growth.

"Well, I think One Belt, One Road is a great idea," Huang said.

"Traditionally, we trade through marine routes, and that's still very important, but One Belt, One Road will create another solution or opportunity for the rest of the world to trade and be better off together.

"One Belt, One Road will help countries along the road be better off together, so why not (support it)?"

The initiative would require extensive infrastructure networks being built in around 60 countries in Asia, Europe and North Africa at an estimated cost of 8 $trillion.

The initiative would connect Asia and Europe's major economic powers on land, as well as via the sea, and is aimed at fostering economic collaboration in the area.

If it becomes reality, the efficiency of trade between countries in the region could double, supporters say.

"If you take a train from Chongqing, in the mid part of China, to Hamburg in Germany, it takes you two weeks, much shorter than the marine route," said Huang, a former executive at Citibank China and Bank of America Merrill Lynch.

"So for high-value products, the railway is actually much more efficient. So it depends on the loading, if you go and come back fully loaded, the cost will come down.

"I think China has been successful in building up infrastructure and that experience can be shared with the countries along the road. So that is why China took the initiative to set up an Asia infrastructure investment bank to let the global partners work together to help those less developed countries."

In his interview with Xinhua, Huang said despite a recent slowdown, China's economy continued to grow. It was problems in the European and U.S. markets that had contributed to slow global growth.

"Europe is not doing well, the United States has not recovered and these two are the major markets in the world," he told Xinhua.

"If these two are not doing well then the global economy is not going to be good. China has been slowing down but still deliver 6.7 percent growth, and only one engine is not enough (to drive a healthy global economy).

"I would say Europe should recover and the United States should completely recover then the world economy will pick up again. Otherwise it is going to be slow."

Not only will the G20 summit prove important for solving the world's economic issues, it is also a key opportunity for China to showcase itself to the world as a great place to do business, Huang said.

"I think it's a good opportunity to introduce China to our partners and find a way to rebuild the global economy," he said.

"It's a good opportunity for the rest of the world to understand China more and for China to understand them more and find a common area in which we can work with each other to help each other and rebuild the global economy."

The G20 summit will take place on September 4 and September 5 and will be attended by the leaders of the world's 20 economies.