* Miners, financials top gainers on benchmark
* Australian banks to buy more govt debt - AFR
Sept 8 (Reuters) - Australian shares rose for a second straight session on Tuesday, as optimism surrounding the development of potential COVID-19 vaccines kept investor sentiment high, with miners and financials leading the charge.
Australia will buy about 85 million doses of two potential COVID-19 vaccines if trials prove successful, Prime Minister Scott Morrison said on Monday, with the first batches of the doses expected to be received by early next year. agreement between Australia and biotech firm CSL CSL.AX to manufacture two potential vaccines came on Monday as Australia reported its lowest one-day rise in new COVID-19 cases since June 26 in the past 24 hours.
The S&P/ASX 200 index .AXJO climbed 1% to 6,007.10 by 0030 GMT in low-volume trade, adding to Monday's 0.3% gain.
About 77.3 million shares had changed hands in early trade, compared with the 30-day average of 767.8 million shares, as stock markets in the United States were closed for a holiday on Monday.
Among gainers, miners .AXMM were the top boosts to the benchmark index, advancing 1.2% on rising iron ore futures and improvement in exports to China, Australia's largest trading partner. IRONORE/ miners BHP Group BHP.AX and Rio Tinto (LON:RIO) RIO.AX gained up to 1.4% each.
Heavyweight financials .AXFJ added 1%, with top lenders Commonwealth Bank of Australia CBA.AX and Westpac Banking Corp WBC.AX rising 1% each.
Meanwhile, the Australian Financial Review reported Australian banks would be required to buy up to A$240 billion ($174.84 billion) of new government debt to boost stability and liquidity levels. added up to 1.5% in its second straight session of gains, helping the healthcare index .AXHJ rise 2.1%.
In New Zealand, the benchmark S&P/NZX 50 index .NZ50 rose as much as 0.5% to 11,916.230.
Heavyweight blue-chip firms were among the top gainers, with Fisher & Paykel Healthcare FPH.NZ and dairy firm a2 Milk Co ATM.NZ adding about 1.2% each.
($1 = 1.3727 Australian dollars)