Sydney, Aug 29 (IANS): Former Australian Prime Minister Kevin Rudd has taken aim at the rise of populist politics around the world, warning that an increase in protectionism will lead to a downturn in global growth.

Addressing a University of Sydney event on Thursday, Rudd told Xinhua news agency that the recent move against free trade, partly engineered by the world view of US President Donald Trump, has acted to re-legitimize protectionism among some people, in a way he never imagined would be possible.

"As a consequence, trade is now growing more slowly than the global economy. Whereas for the previous 40 years, trade growth actually drove global economic growth," he said.

"So we have economies such as ours (Australia) bumping along the bottom with 1-2 per cent growth and many other developed economies much the same, because trade is no longer playing the role it did."

With the current Australian Prime Minister Scott Morrison set to travel to Washington in September as part of an official visit, Rudd urged him to use the two countries' "special relationship" to engage with Trump on the issue of the trade war.

"If you're serious in prosecuting the country's and frankly the world's economic interests at the moment, you must use the avenue of this special relationship between Australia and the US... to argue a very simple conservative proposition, free trade."

"So the central message for Prime Minister Morrison is to say that free trade... does legitimately raise global living standards, including for this country (Australia) as well. He (Morrison) has to engage that up front, in my judgment," Rudd added.