* April-June premium the highest in 2 years
* Local spot premiums rise, reflect higher overseas premiums
* Producers' initial proposals were at $135/T (Adds comments and details)
By Yuka Obayashi
TOKYO, March 29 (Reuters) - Japan's aluminium premium for shipments during the April to June quarter has been set at $128 per tonne, up about a third from the quarter before due to higher overseas prices, five sources directly involved in the pricing talks said on Wednesday.
Japan is Asia's biggest importer of aluminium and the premiums, which consumers pay to producers on top of the London Metal Exchange cash price for primary metal shipments, set the benchmark for the region.
The new premium is 35 percent higher than the $95 per tonne premium PREM-ALUM-JP in the previous quarter and is the second quarterly increase in a row and the highest in two years.
"We've signed the deals at $128 a tonne with all of the producers whom we've talked to," a source at an end-user said. He declined to be named due to the sensitivity of the talks.
A source at a producer said all of his company's customers had agreed to contracts at $128 a tonne this week.
The quarterly pricing negotiations began last month between Japanese buyers and global producers, including Rio Tinto ,, South32 and Alcoa Corp, with offers at $135 a tonne.
The increase comes after U.S. and European spot premiums have risen by about $20 to $50 per tonne over the past few months amid output disruption at Alcoa's Portland smelter and a production cut at Rio's Boyne smelter in Australia where costs of power have been rising.
Buyers were initially seeking premiums between $110-115 a tonne, but compromised after local spot premiums climbed $10-20 a tonne in the past month, a source at a trading house said.
"Local premiums rose during the talks after producers have changed destination of some shipments to the U.S. where the spot premiums were higher than Asia," he said.
Producers were also forced to trim their offers as buyers were not feeling supply tightness that much, buyer sources said.
Aluminium stocks at three major Japanese ports rose 3.3 percent to 282,000 tonnes in February from the previous month, according to trading house Marubeni.
"Still, overall demand for aluminium is pretty healthy here, backed by wider use of the metal in automobiles," Akio Hamaji, chairman of the Japan Aluminium Association, told a news conference on Wednesday.
The association said the country's demand for aluminium products rose 1.7 percent in the financial year ending this month and would increase 0.7 percent next year to 4.156 million tonnes. (Reporting by Yuka Obayashi; Editing by Christian Schmollinger and Mark Potter)