* Dollar finds broad support in Asia session
* Weak Japan, Thailand data keeps lid on optimism
* Euro nurses losses after weak manufacturing reading
* RBA Gov speech eyed
* Graphic: World FX rates in 2019 tmsnrt.rs/2egbfVh
By Tom Westbrook
SINGAPORE, Sept 24 (Reuters) - The dollar held firm on Tuesday as the euro struggled on more signs of economic trouble in the euro zone, while sterling wallowed near one-week lows before a key Supreme Court ruling related to the suspension of Britain’s parliament this month.
Traders were also keeping a watchful eye on Sino-U.S. trade talks which is set to resume next month, with constantly-shifting expectations on the prospect of a deal keeping markets on edge in the past month.
The dollar rose slightly against the yen to 107.59 and inched higher against a basket of currencies to 98.664. It was steady against the euro, which stayed under $1.10 mark where it had fallen on Monday following dismal readings on German manufacturing.
Sterling was also under the gun, wallowing at $1.2429, near a one-week low, ahead of a UK Supreme Court ruling due around 0930 GMT.
The court will rule on whether Prime Minister Boris Johnson acted unlawfully when he suspended parliament just weeks before Brexit, with the case’s outcome potentially complicating his plans to lead his country out of the European Union next month.
Overall, traders were cautious in light of the Brexit uncertainty, Sino-U.S. trade talks and a slowing global economy.
Data in Asia further underscored the fragility of growth across key economies. Japanese manufacturing activity shrank at the quickest pace in seven months September, while Thailand also posted a sharper-than-expected drop in production in August.
U.S. Treasury Secretary Steven Mnuchin told Fox Business that discussions were scheduled in two weeks and that he and U.S. Trade Representative Robert Lighthizer would meet Chinese Vice Premier Liu He.
“The Street wants these talks to make progress, so I would expect in the run-up, if there’s progress, then we’ll see a rally in emerging markets currencies,” said Jeffrey Halley, senior analyst for Asia Pacific at OANDA by phone from Jakarta.
“But I think the currency markets are in a bit of a holding pattern...they’re definitely marking time,” he said.
The Australian and New Zealand dollars were steady ahead of a speech by Reserve Bank of Australia Governor Phil Lowe at 1005 GMT, with the market expecting a dovish tone after weak jobs data last week lifted expectations of an imminent rate cut.
Both currencies sat near three-week lows, with the Aussie buying $0.6781 and the kiwi lifting slightly to $0.6302.
“We think Lowe will provide a strong signal that the RBA is ready to cut rates again, endorsing our view for a 25bp cut in October,” said Tapas Strickland, a director of economics and markets at National Australia Bank in Sydney.
“Any comments on the scope for unconventional policy will also be critical for the market.”
China’s yuan strengthened slightly to 7.1085.
A Bloomberg report, citing sources, saying China had granted several domestic firms new tariff waivers for U.S. soybean imports sent the Chinese currency higher in afternoon trade.
Reporting by Tom Westbrook Editing by Shri Navaratnam