Aussie at $1.0455, having peaked to $1.0498 in early Australasian trade, its highest since late March, as investors place high hopes the ECB may resume buying the bonds of debt-ridden nations.
NZ dollar at $0.8073 after clocking a near three-month high of $0.8115 early.
ECB president last week vowed the central bank was ready to do whatever it takes to preserve the euro.
Markets are pricing in the chance of Fed QE and aggressive ECB action later this week when they meet. But markets have been disappointed many times before and with Germany's Economy Minister warning the ECB about any large-scale government bond purchases. Some analysts have doubts about seeing fresh action.
A trader says risk currencies could be stretched due to exaggerated central bank expectations. Aussie and kiwi have gained more than 8 pct in two months.
Media reports mining giant BHP Billiton is likely to delay a $30 bln proposed expansion of a copper and uranium mine in South Australia.
Recent steep falls in iron ore and coal prices, Australia's top exports, are causing some miners to pause. Australia has more than A$450 billion of resources investments in the pipeline, with more than half already committed or under construction.
Aussie testing support at $1.0445, with buyers tipped between $1.0425-45.
Kiwi may test $0.7991, the low on July 27, after breaking through $0.8083 retracement level, while traders anticipate some offers around $0.8150, which could cap near-term gains.
Aussie & kiwi hover near all-time highs versus the euro . Against the yen, Aussie at 82.00 yen , having flirted close to a three-month peak hit on Friday at 82.36.
Antipodeans are on fire against the Swissy, with the kiwi at 0.7887 francs, having hit a 2-year high of 0.7915, while the Aussie last trades at 1.0216 francs, having rocketed through a five-year peak of 1.0263 last week.
NZ's number of new dwelling consents approved rose for the first time in three months in June, driven in part by building in the earthquake damaged Canterbury region.
No impact on rate outlook. Markets pricing implies 16 pct chance of a rate cut in September due to the euro zone crisis, while analysts see a rise next year as the next move.
The latest data on currency positioning by market speculators suggest the Aussie, kiwi are poised for more gains. IMM data shows speculators net long positions in the Aussie roughly doubled in the week ended Tuesday.
Kiwi net long positions also rose, indicating speculative investors continue to buy the two currencies. An excessively high number of long positions raises the risk of a reversal of those positions, which can trigger a sharp sell-off.
Australian government bonds ease, with the three-year contract down 0.130 points at 97.470, while the 10-year contract off 0.090 points to 97.000.
New Zealand government bonds also fall, pushing yields around 10 basis points higher across the curve.