Japanese police investigators are in Brazil to ask for the country's cooperation over a case of a Brazilian national suspected of killing his wife and daughter in a western Japanese city.

Officials of the Osaka police and the National Police Agency arrived in the capital Brasilia on Sunday night.

They are looking for the 33-year-old suspect, Barbosa Anderson Robson, who is believed to be hiding in Brazil.

The man is on an international wanted list for allegedly stabbing to death 29-year-old Aramaki Manami and 3-year-old Lily in their home in Sakai City, Osaka Prefecture, in August.

He was found to have left for Brazil, but his whereabouts have remained unknown since then.

The Japanese officials plan to brief Brazilian police authorities on the case and ask for their cooperation.

There is no extradition treaty between the two countries. The officials may ask for the suspect to be prosecuted under Brazilian law if he does not return to Japan.