Four Japanese companies joined together Wednesday in a bid to create a mainstream market for robots and to stay a step ahead of rising competition from South Korea.

The companies -- Tmsuk, ZMP, VStone, Business Design Laboratory Co (BDL) -- said they were forming a loose federation to exchange technology with one another and market their products together overseas.

Japan has been a leader in robotics, frequently making headlines for humanoids that do everything from playing the violin to babysitting to helping the elderly.

But while industrial robots are commonly put to use in Japan, companies have struggled to find a mass consumer market for humanoids, in part because of the prohibitive costs.

The companies said they together hoped to sell a total of 200,000 to 300,000 robots within the next five years, some 10 times what they sell now.

"In the coming decade, we believe robots will widely enter into our everyday lives. They have proven to be effective in services, education and entertainment," the four companies said in a joint statement.

"However, in order to expand their contribution to the overall national economy, it is essential not to stop at research and development but to directly engage in market operations," the newly created Federation for the Market Creation of Next-Generation Robots said.

As Japan ages, household robots could include BDL's "ifbot," a white robot with green eyes and a flashing smile that can prevent dementia among the elderly by quizzing them, singing songs or giving health advice.

Tmsuk president Yoichi Takamoto warned Japan's standing could be overtaken by high-tech neighbour South Korea, which has set a goal of a robot in every household by as early as 2013.

"I think that Japan's robotics technology is still number one, but I'm not sure how long that will be. South Korea is working quite hard in this field," said BDL president Kenji Kimura.

The companies complained that Japan has not supported robotics in the same way as South Korea, which last year set up a 100 billion-won (10 million-dollar) fund to encourage innovation and is planning the world's first robot theme park by 2013.

"In Japan we are trying to start a robot business but at this rate, I don't know whether that will ever happen," Tmsuk's Takamoto said.