Global mining giant Rio Tinto said Thursday it was not worried by talk of China's economy slowing and would press ahead with plans to expand its iron ore business, saying signs were robust on the ground.

Rio iron ore chief Sam Walsh said the miner expected China to grow eight percent this year and demand for minerals to hold up, dismissing downbeat talk about the Asian superpower's prospects.

"I know there are a lot of people who are passing doom on that, but we're just not physically seeing that on the ground," Walsh said in a speech in Sydney.

"We see the iron ore business as being a very robust business... continuing in the short-term and long-term," he added, describing the market as "steady as she goes".

Walsh said Rio was continuing to ship "flat out with very good production" as countries including Indonesia, the Philippines, Thailand and Brazil ramped up their urbanisation.

The proximity of its flagship Australian operations to those nations put Rio in the "box seat" he added, with a number of expansion projects planned or underway.

"These are things that we're continuing to work on and I'd expect that they'd improve," he said.

Data out of China points to a slowing in the world's second-largest economy, with manufacturing contracting in May for the seventh consecutive month as woes in key export markets such as Europe and the United States hit overseas sales.

Beijing has set a target of 7.5 percent economic growth this year, down from 9.2 percent last year and 10.4 percent in 2010.

Rio Tinto chairman Jan du Plessis said earlier this month that he was more confident about the global outlook than six months ago and expected demand for commodities to double over the next 20 years.

Du Plessis said China was cooling relative to recent years but its growth was still very favourable by global standards, with long-term demand for raw materials seen as very strong.