* Base metals, financials lead gainers
* Gold stocks retreat for 2nd straight session
* TPG plunges as regulator flags merger concerns
By Aby Jose Koilparambil
Dec 13 (Reuters) - Australian shares pulled ahead on Monday, though buyers lacked conviction after two sessions of solid gains as investors looked to more developments on Sino-U.S. trade talks amid tentative signs of easing tensions between the two economic giants.
The S&P/ASX 200 index .AXJO climbed 0.3 percent or 16.3 points to 5,669.80 by 0053 GMT with base metals and financial stocks .AXFJ leading the gains. The benchmark ended 1.4 percent higher on Wednesday.
Markets were cautiously optimistic on progress in Sino-U.S. trade talks, helping spur Wall Street higher overnight.
The Chinese purchase of at least 500,000 tonnes of U.S. soybeans on Wednesday came as the latest sign of easing trade tensions between the two countries. is a bit of caution. We had a strong session yesterday and markets were a little bit ahead of the curve. Today, the market hasn't kicked on yet," said Christopher Conway, senior investment advisor at Marcus Today.
"Investors want more concrete concessions (in trade war) ... So far, it has been all incremental gains, that could hopefully lead up to a final deal," he said.
Australia's resource-rich economy is heavily exposed to the Chinese market, so any drag in growth in the Asian superpower risks harming local businesses and overall growth.
Diversified mining giants BHP Group BHP.AX and Rio Tinto (LON:RIO) RIO.AX boosted the sector index, strengthening as much as 1.1 percent and 1.21 percent, respectively.
Gold stocks extended their slide for a second successive session following a recent rally. The losses pulled the index .AXGD down as much as 1.6 percent, with St. Barbara SBM.AX falling over 6 percent to be the top percentage loser.
Financials rose as much as 0.7 percent with Australia and New Zealand Banking Group ANZ.AX rising 1.4 percent and National Australia Bank NAB.AX up 1.1 percent.
TPG Telecom Ltd TPM.AX plunged, losing as much as about 19 percent, its biggest intraday percentage loss in over two years, after Australia's competition regulator expressed preliminary concerns about its proposed merger with Vodafone Group's VOD.L Australian business. TPG was the top percentage loser on the benchmark. L3N1YH5MW
Across the Tasman Sea, New Zealand's benchmark S&P/NZX 50 index .NZ50 rose 0.6 percent or 55.79 points to 8,794.15.
Seafood business firm Sanford Ltd SAN.NZ was the top performer in terms of percentage gains, rising as much as 3.2 percent.