New Zealand looks unlikely to follow Australia and join the world's biggest emissions trading scheme.
In August, Australia announced it would link its carbon trading scheme to Europe's in 2015, allowing Australian credits to be sold into the $100 billion market from 2018.
An adviser on carbon markets at the European Commission in Brussels, Damien Meadows, says New Zealand's policy of allowing unlimited imports of credits from overseas, including developing countries, is a barrier to linking with Europe's scheme.
The commission doubts all these credits actually reduce emissions of carbon dioxide into the atmosphere.
"I think it's important for a common approach to be taken by the time systems are linked," Mr Meadows says.
Online carbon trader Lizzie Chambers says Europe's stance is a shame, as local carbon farmers hard hit by record low carbon prices desperately need new markets to sell to.
Climate Change Minister Tim Groser says the Government is to consider further bans on imported carbon credits.