WELLINGTON, June 16 (Reuters) - Global dairy prices plateaued...

WELLINGTON, June 16 (Reuters) - Global dairy prices plateaued as whole milk prices dropped on Thursday at the second dairy auction held in June.

The Global Dairy Price Index was unchanged at $2,339 after rising for two consecutive auctions.

"The GDT result indicates the market is still weak which is a concern as offer volumes are forecast to lift in the current months as more new season product is offered," said AgriHQ dairy analyst Susan Kilsby.

"In the current environment it is difficult to see prices move substantially higher before the end of the year."

Whole milk power lost 4.5 percent, while skim milk powder rose 1.5 percent and butter rose 5.3 percent.

A total of 23,089 tonnes was sold at the latest auction, falling 4.0 percent from the previous one.

Dairy giant Fonterra (FCG) last month forecast a farmgate milk price for the 2016/2017 season of NZ$4.25, up from NZ$3.90 in the season just ending, however this was still below an estimated break-even level of NZ$5.28.

Until recently, dairy was the backbone of New Zealand's economy, representing around 25 percent of exports. But prices have tumbled by more than half since early 2014, hurt by China's economic slowdown and global oversupply.

Weak dairy prices have put significant pressure on New Zealand farmers. More than 85 percent of dairy farmers were already estimated to be running at a loss.

The auction results can affect the New Zealand dollar as the dairy sector generates more than 7.0 percent of the nation's gross domestic product.

The Kiwi rose to $0.7037 percent from as low as $0.6963 overnight, though analysts said that much of that strength was in response to the U.S. Federal Reserve's decision to hold interest rates.

The auctions are held twice a month, with the next one scheduled for July 5.