Foreign judgments may be enforced at common law by an action or counterclaim. The simplest action is an application for summary judgment. 

For judgments to be enforceable they must be final and conclusive and the foreign court's jurisdiction must be recognised under New Zealand law. They must also be for a debt or other sum of money. If mere arithmetical calculation is required to fix the sum, it is treated as being ascertained. However, if the judgment orders the defendant to do anything else, such as perform a contract, it is not enforceable at common law. 

A foreign judgment is regarded as final and conclusive, even though it is subject to an appeal, and even though an appeal against it is actually pending in the foreign country where it was given. A judgment will not be regarded as final and conclusive however if the foreign court retains the power to review or vary its own order in the future. 

The defendant cannot raise, by way of defence, any matter which could have been raised in the foreign court (even if it were not raised). 

The enforcement of a foreign judgment can be opposed on any of the following grounds:

• Fraud by the party in whose favour the judgment is given or fraud on the part of the court pronouncing the judgment.
• Lack of jurisdiction (in the view of the New Zealand court) by the court of the foreign country.
• Enforcement or recognition of the judgment being contrary to New Zealand public policy.
• Breach of natural justice in the proceedings in which the judgment was obtained. 

Generally, a court of a foreign country is regarded as having jurisdiction to give a judgment capable of enforcement or recognition in New Zealand in any of the following cases: 

•  if the judgment debtor was, at the time the proceedings were instituted, resident (or, in the case of a company, had a place of business) in the foreign country
• if the judgment debtor was plaintiff, or had counter-claimed, in the proceedings in the foreign country
• if the judgment debtor, being a defendant in the foreign court, submitted to the jurisdiction of that court by voluntarily appearing in the proceedings
• if the judgment debtor, being a defendant in the original court, had before the commencement of the proceedings agreed, in respect of the subject matter of the proceedings, to submit to the jurisdiction of that court or the courts of that country.

In general, a foreign judgment which is final and conclusive on the merits cannot be impeached for any error either of fact or of law. A foreign judgment cannot, in general, be impeached on the ground that the court which gave it was not competent to do so according to the law of the foreign country concerned.