The Morgan Foundation's calling on the Government to stop passing the buck when it comes to dodgy carbon credits.

The Foundation has released a report naming some of New Zealand's biggest companies as having bought credits out of Russia and the Ukraine.

They were used to offset carbon emissions here at a much cheaper rate.

Foundation General Manager Geoff Simmons said companies including BP, Z, Fonterra and NZ Steel bought millions of credits - which have no environmental value.

"We were the only country that allowed these dodgy foreign credits to be used in our emissions trading scheme."

"By naming and shaming these companies, we're really hoping that they will get in behind our call for the government to dump these junk credits."

Both BP and Z said they've worked within the rules set by the Government.