SYDNEY, May 31 (Reuters) - The Australian and New Zealand dollars took a breather on Friday after a week of choppy trading, with a disappointing survey on Chinese manufacturing providing another reason for caution.

China's official purchasing managers' index (PMI) unexpectedly slipped into contraction at 49.5 in May, a blow to hopes the Asian giant was finally picking up steam.

Much now depends on a key reading of U.S. inflation due later in the session that could make or break the case for a Federal Reserve rate cut as early as September.

The Aussie was flat at $0.6633, after edging up 0.3% overnight, little changed on the week after ricocheting between support at $0.6591 and resistance around $0.6680.

The kiwi dollar was a shade firmer at $0.6121, having bounced from a $0.6090 low the previous session. Resistance lies at the recent 10-week top of $0.6170, with support at $0.6084.

A rally in U.S. Treasuries supported risk sentiment and gave a much needed reprieve to local bonds, where yields had been shoved to four-week highs.

Three-year bond futures bounced to 95.950, from a 95.870 low, leaving them down 7 ticks for the week.

The outlook for Australian interest rates have also waxed and waned this week as markets turned super-hawkish on a surprisingly high inflation reading, before relaxing a little amid softer U.S. data.

Futures are back to implying a 12% chance of a hike from the Reserve Bank of Australia (RBA), down from 27% on Thursday. The first easing is now seen as likely from May next year, compared to September a day before.

Many analysts are more dovish, still tipping a move before Christmas.

"It will take time for enough evidence to accumulate to convince the Board that the disinflation is on track," said Luci Ellis, chief economist at Westpac.

"But if things turn out as we expect, a forward-looking central bank would want to start reducing the restrictiveness of policy by about November."

Data due next week is expected to support the case for cuts, with economic growth seen near to stalling in the first quarter.

Markets have also pushed out the expected timing of a rate cut from the Reserve Bank of New Zealand (RBNZ). A quarter-point easing is seen as only a 37% chance for October, but is fully priced for November.

New Zealand's central bank itself is projecting steady policy all the way to mid-2025. (Reporting by Wayne Cole; Editing by Tom Hogue)