Wal-Mart Stores Inc said on Thursday it was taking more steps to make sure its toys are safe after Mattel Inc's recall this month of millions of Chinese-made toys.

The world's largest retailer will ask all toy suppliers to resubmit testing documentation for toys on its shelves or on the way to its stores, it said in an e-mailed statement.

It also said it has hired independent laboratories to conduct an average of 200 additional tests each day. Those labs, Bureau Veritas, Intertek and Consumer Testing Laboratories, are already used by both Wal-Mart and its suppliers, spokeswoman Melissa O'Brien said.

The extra testing capacity will be used to help smaller toy brands who may not have access to such testing and also to test other products as Wal-Mart deems necessary, O'Brien added.

The company said it would share results with retailers and manufacturers, and it planned to work with the Toy Industry Association to support new measures aimed at ensuring higher safety standards.

The announcement came a few hours after a U.S. House of Representatives panel said it would hold a September 19 hearing on China-made toys.

Wal-Mart Watch, which has been pushing for reforms to benefit Wal-Mart workers, said the retailer's proposals did not go far enough.

Due to the tremendous pressure that Wal-Mart puts on its suppliers to keep costs low, manufacturers are forced to move production overseas and cut corners on safety, Wal-Mart Watch Executive Director David Nassar said in a statement.

Mattel, the maker of Barbie dolls, Hot Wheels and Fisher Price toys, this month recalled millions of toys made in China due to lead paint and hazards from small, powerful magnets that can be swallowed and cause injury. That came two weeks after it recalled 1.5 million Fisher Price preschool toys because paint on them may have contained excessive amounts of lead.

Mattel has said it is putting suppliers under a microscope, requiring every batch of paint at each vendor to be tested, stepping up random factory inspections, and testing to make sure every production run of toys complies with its standards.

(Reporting by Robert MacMillan and Nicole Maestri in New York and Nichola Groom in Los Angeles)