WELLINGTON (Reuters) - New Zealand's Prime Minister John Key brushed off suggestions by opposition party to print money to lower the country's strong currency because it would create inflation and increase business costs.

"The latest idea of the Green (Party) to print money that is a pretty whacky idea," Key told Television New Zealand on Monday.

"Printing money makes you rich. Zimbabwe would be the richest country on the planet and it's not."

Key reiterated inflation remains the primary focus of the country's monetary policy, adding that increasing money supply would raise inflation.

"That means your interest rates will go up. Your mortgage costs will go up, your business costs will go up. The costs of everything you buy will go up," he said.

"It might bring your currency down, it might be a by-product of that, but it's quite a cost and risk to the consumers."

Key said New Zealand's economy was not in a "bad shape", adding that it was growing at one of the fastest rate in the countries grouped under OECD.

(Reporting by Mantik Kusjanto)