WELLINGTON (Reuters) — New Zealand's central bank has ordered a British finance firm to stop calling itself a bank.

ABN Union Bank, a British registered company, was not a registered bank in New Zealand and could not use the term in doing business in the country, the Reserve Bank of NZ (RBNZ) said in a statement.

ABN Union, which has no connection to the Dutch based ABN AMRO financial group, had been ordered to stop using the term "bank" immediately, the RBNZ said.

New Zealand has 16 registered banks, which must comply with RBNZ rules on maintaining levels of capital and infrastructure.

An RBNZ spokeswoman said it was not known precisely what business the company had been doing in New Zealand.

According to its website, ABN Union Bank offers a range of private banking services to medium-sized businesses and high net worth investors.

It says it was based in Latvia with agents in Bermuda, Malaysia and New Zealand.