* NZD five cents lower vs USD since July

* AUD at 9-month peak vs kiwi

* Aussie government yield curve at flattest in over a year

By Naomi Tajitsu and Cecile Lefort

WELLINGTON/SYDNEY, Aug 26 (Reuters) - The New Zealand dollar plumbed six-month lows on Tuesday as a surprisingly large trade deficit provided speculators with a fresh excuse to sell, while its Australian cousin held its own in the face of a broadly stronger U.S. dollar.

The kiwi extended losses to as far as $0.8311 NZD=D4 , its weakest since late February. It was last at $0.8343 and has shed more than 5 cents since it hit a three-year peak in July.

It moved a notch lower after data showing a larger-than-expected trade deficit in July highlighted the ongoing fall in dairy prices, the country's main export earner. ID:nnW9N0NZ02N

The kiwi underperformed most major currencies, particularly the Aussie AUDNZD=R which hit a nine-month high around NZ$1.1170.

Against a currency basket =NZD the kiwi fell to 78.52, its lowest since March and well below the Reserve Bank of New Zealand's quarterly projections. ID:nL5N0QQ55Z

"The kiwi is still strong, but the decline is reflecting a few things catching up with it," said ASB economist Chris Tennent-Brown.

On the whole, he said, the New Zealand dollar is facing pressure from an on-hold policy stance by the central bank, and "dairy prices and the broader export outlook losing a lot of its gloss over the last six months."

He sees the next target at $0.8242, a low hit in February, and below that the year's trough at $0.8052.

Technical signs pointed to further selling after it broke support at $0.8353, the 61.8 percent retracement of its February-July rally.

The kiwi offered limited initial reaction to a statement from Standard Poor's reaffirming its sovereign rating and outlook on New Zealand. ID:nW9N0PX01A

The Australian dollar was relatively stable at $0.9293 AUD=D4 , having bounced from a low of $0.9272 in early trade.

It has showed remarkable resilience in recent days against a broadly rising U.S. dollar and remained well within the 92-95 cent band seen since March. Support was found at $0.9270, with resistance around $0.9315.

It stayed strong on the euro at A$1.4200 EURAUD=R , after touching a 9-month peak of A$1.4181.

Charts are bearish on the euro and a break of A$1.4043 would open the way to A$1.3859 and then to A$1.2213, the 2013 trough. The euro has been pressured by rising expectations of another round of policy easing by the European Central Bank.

The Aussie retreated from a near 15-month high of 97.27 yen AUDJPY=R to be at 96.51.

New Zealand government bonds 0#NZTSY= rallied, tracking gains in U.S. Treasuries and pushing yields on most maturities 4.5 basis points lower.

Australian government bond futures bounced, with the three-year bond contract YTTc1 up 3 ticks at 97.340 and off a three-week low. The 10-year contract YTCc1 added 6 ticks to 96.635 in a bullish flattening of the curve.

The premium offered by Australian 10-year yields AU10YT=RR over 3-year yields AU3YT=RR has shrunk to its smallest in over a year at 70 basis points. That compares with a peak of 136 basis points early in January.

(Editing by Shri Navaratnam) ((Cecile.Lefort@thomsonreuters.com)(+61 2 9373-1234)(Reuters Messaging: cecile.lefort.thomsonreuters@reuters.net))

Keywords: MARKETS AUSTRALIA/FOREX