FOREX-Yen in surprise rebound; NZD lifted by GDP

* Yen rebounds as selloff post-BOJ easing fades

* Solid NZ GDP gives kiwi dollar a boost

* HSBC's China PMI report next in focus

By Ian Chua

SYDNEY, Sept 20 (Reuters) - The yen held gains in Asia on Thursday after staging a surprise bounce as an initial selloff in reaction to the Bank of Japan's policy easing fizzled, while upbeat growth data gave the New Zealand currency a shot in the arm.

The dollar bought 78.39 yen, having retreated from a one-month high of 79.23 set on Wednesday after the BOJ boosted its asset-buying programme to help fuel the country's economic recovery.

The yen also regained some ground on the euro and commodity currencies, pushing the single currency down to 102.30 from a high of 103.63. The Aussie dollar dipped to 82.07 yen from 82.94.

The rebound in the yen was a setback for Japanese authorities, who had been quick to complain about the currency's strength in the wake of the U.S. Federal Reserve's own bond-buying programme announced last week.

In trying to rationalise the move, some analysts pointed to the set limit in the BOJ's programme, in contrast to the open-ended nature of the Fed's.

"The ECB's and the Fed's plans are unlimited in nature, while the BOJ's is capped at a paltry 10 trillion yen," noted Christopher Vecchio, currency analyst at DailyFX.

Traders said the Fed's plan has certainly had more success in keeping the greenback pinned down. The dollar index stood at 79.102, still struggling to pull away from a six-month trough of 78.601 set last Friday.

The euro, meanwhile, stood at $1.3047, hovering below a four-month peak of $1.3173 reached on Monday in a range-trade as markets wait to see if Spain will seek a bailout and activate the European Central Bank's bond-buying programme.

In contrast, New Zealand-dollar bulls were cheered by data showing the country grew at a healthy 0.6 percent in the second quarter, double the expected pace.

The kiwi dollar gained around 40 pips to a session high of $0.8300. Initial resistance is seen at $0.8354, a six-month high set last Friday.

The kiwi outperformed its Australian counterpart, which fell to NZ$1.2620 from an early high of NZ$1.2710. Against the greenback, the Aussie was at $1.0475, still off Friday's high of $1.0625.

The market is waiting for HSBC's latest report on China's manufacturing sector due around 0230 GMT. Further signs of a slowdown there will keep the Aussie under pressure as China is Australia's single largest export market.