Diplomats are not expecting immediate change in New Zealand's ties with Iran, despite the international agreement on Iran's nuclear program.

The Ministry of Foreign Affairs is welcoming the deal but said nothing will immediately change for New Zealand business dealings with Iran.

The ministry said once sanctions are lifted and an agreement is fully implemented, it is hoped the relationship between New Zealand and Iran will progress, particularly in the trade and economic space.

Until the UN sanctions are lifted the Ministry of Foreign Affairs said the existing rules for doing business with Iran - including the obligation to register with the ministry - will remain in place.