China has approved a dozen new free trade zones months after opening its first one in Shanghai, state media said Wednesday, furthering efforts to test economic reforms and bolster growth.

Beijing "has given the nod to 12 free trade zones ... amid a spurt of nationwide enthusiasm for such schemes," the official news agency Xinhua reported.

The sites will include the megacities of Tianjin near the capital and Guangdong in the south close to Hong Kong, the report said, citing an unnamed source -- who declined to name the remaining 10 locations.

The new zones will have to conduct a survey and draw up specific plans "in a process that may last more than a year", Xinhua added.

The free trade zone in Shanghai opened last September with great fanfare. It covers a 29-square-kilometre (or 11-square-mile) area.

Authorities touted it as a site to try out reforms, such as allowing free convertibility of the yuan currency to loosening restrictions on foreign investment.

Such changes are being closely watched as a test of China's ability to restructure its economy in the face of slowing growth.

But soon after the launch a "negative list" was issued of what is barred in the zone, eliciting criticism that it was too long and restrictive.

Officials later promised that a revised list would be released in 2014.