* Healthcare and consumer firms weigh on the index

* IOOF to buy NAB's wealth unit for $1.1 bln

* NZ bourse loses most in over a week

Aug 31 (Reuters) - Australian shares seesawed on Monday, as investors remained cautious ahead of the central bank's cash rate decision and second-quarter economic growth data expected this week to gauge the impact of the COVID-19 pandemic domestically.

The S&P/ASX 200 index rose 0.2% to 6,083.60 by 0100 GMT, with gains capped by rising worries of an economic recovery as the country reported a record daily rise in coronavirus-related deaths.

Reserve Bank of Australia, set to meet on Tuesday, is expected to hold the cash rate at its all-time low.

Meanwhile, GDP data for the second quarter on Wednesday is likely to reflect the worst of the pandemic's impact.

Analysts at ANZ expect the economy to shrink 5.8% in the June quarter from a year ago, while a Reuters poll forecasts the contraction at 5.3%, compared with a growth of 1.4% in the March quarter.

The biggest drags on the main index were healthcare firms, which fell as much as 0.9% to hit their lowest in about two weeks.

Heavyweight CSL Ltd slipped 0.8%, while ASX-listed shares of Resmed Inc gave up 1.3%.

Gold stocks were among the gainers, rising as much as 2.5%. Newcrest Mining gained 2.7% and Northern Star Resources rose 3%.

National Australia Bank gained 0.8% after wealth manager IOOF Holdings announced the acquisition of its wealth management business for A$1.44 billion ($1.06 billion).

Across the Tasman Sea, New Zealand's benchmark S&P/NZX 50 index slipped 0.6%, or 72.94 points, to 12,020.58 as of 1230 GMT.

The bourse's website crashed for a fifth day in row on Monday, after a series of cyber attacks last week hit the bourse's ability to operate normally.

Financials and healthcare firms dragged down the index, with NZ-listed shares of Westpac Banking Corp losing up to 1% and Fisher & Paykel Healthcare Corp shedding up to 2.4%.

(Reporting by Sameer Manekar in Bengaluru; Editing by Amy Caren Daniel)