Mexico is close to lifting a ban on imports of poultry products from four out of eight US states on which the ban was imposed following an outbreak of bird flu.

Javier Trujillo, the head of the Mexican government’s animal health commission, told Reuters that Pennsylvania, North Carolina, Virginia and West Virginia have complied with Mexico’s requests for proof that the states are free of avian influenza.

"They have submitted a dossier showing they have returned to a situation where they are free of avian influenza, which they handed over to us in March and which we studied during April," Trujillo said.

He added that the four states still need to prove they can control movement of poultry products from other states into their own.

Texas, California, Maine and Connecticut had not yet supplied proof that they are free of the highly contagious disease, Trujillo said.