SYDNEY (Reuters) - Asian share markets made a wary start to the week on Monday as investors navigated the shifting sands of White House tariff policy, while awaiting key U.S. jobs data and a widely expected cut in European interest rates.

There was little obvious reaction to President Donald Trump's threat late Friday to double tariffs on imported steel and aluminium to 50%, beginning on June 4, a sudden twist that drew the ire of European Union negotiators.

Speaking on Sunday, Treasury Secretary Scott Bessent said Trump would soon speak with Chinese President Xi Jinping to iron out a dispute over critical minerals.

White House officials continued to play down a court ruling that Trump had overstepped his authority by imposing across-the-board duties on imports from U.S. trading partners.

"The court ruling will complicate the path ahead on trade policy, but there remains an ample set of provisions available to the administration to deliver its desired results," said Bruce Kasman, chief economist at JPMorgan.

"There is a commitment to maintaining a minimum U.S. tariff rate of at least 10% and imposing further sector tariff increases," he added. "An increase in ASEAN to discourage transhipment looks likely, and the bias for higher tariffs on US-EU trade persists."

Markets will be particularly interested to see if Trump goes ahead with the 50% tariff on Wednesday, or backs off as he has done so often before.

In the meantime, caution reigned and MSCI's broadest index of Asia-Pacific shares outside Japan went flat. Japan's Nikkei fell 1.1%, while South Korean stocks dipped 0.1%.

S&P 500 futures eased 0.2% and Nasdaq futures lost 0.3%. The S&P climbed 6.2% in May, while the Nasdaq rallied 9.6% on hopes final import levies will be far lower than the initial sky-high levels.

Front-running the tariffs has already caused wild swings in the economy, with a contraction in the first quarter likely turning into a jump this quarter as imports fall back.

The Atlanta Fed GDPNow estimate is running at an annualised 3.8%, though analysts assume this will slow sharply in the second half of the year.

Data this week on U.S. manufacturing and jobs will offer a timely reading on the pulse of activity, with payrolls seen rising 130,000 in May while unemployment stays at 4.2%.

EYEING UNEMPLOYMENT

A rise in unemployment is one of the few developments that could get the Federal Reserve to start thinking of easing policy again, with investors having largely given up on a cut this month or next.

A move in September is seen at around a 75% chance, though Fed officials have stopped well short of endorsing such pricing. There are at least 11 Fed speakers on the diary for this week, led by Fed Chair Jerome Powell later on Monday.

Fed Governor Christopher Waller did say on Sunday that cuts remain possible later this year as he saw downside risks to economic activity and employment and upside risks to inflation from the tariffs.

A softer jobs report would be a relief for the Treasury market, where 30-year yields continue to flirt with the 5% barrier as investors demand a higher premium to offset the ever-expanding supply of debt.

The Senate this week will start considering a tax-and-spending bill that will add an estimated $3.8 trillion to the federal government's $36.2 trillion in debt.

Across the Atlantic, the European Central Bank is considered almost certain to cut its rates by a quarter point to 2.0% on Thursday, while markets will be sensitive to guidance on the chance of another move as early as July.

The Bank of Canada meets Wednesday and markets imply a 76% chance it will hold rates at 2.75%, while sounding dovish on the future given the tariff-fuelled risk of recession there.

Widening rate spreads have so far offered only limited support to the U.S. dollar.

"The greenback remains near the lower end of its post-2022 range and considerably weaker than interest rate differentials would imply," noted Jonas Goltermann, deputy chief markets economist at Capital Economics.

"Sentiment around the greenback remains negative and it continues to look vulnerable to further bad news on the fiscal and trade policy fronts."

On Monday, the dollar had dipped 0.2% on the yen to 143.79, while the euro edged up a fraction to $1.1353. [USD/]

The greenback also slipped 0.1% on the Canadian dollar to 1.3727, getting no tailwind from Trump's threat of 50% tariffs on Canadian steel exports.

In commodity markets, gold edged up 0.6% to $3,310 an ounce, having lost 1.9% last week. [GOL/]

Oil prices bounced after OPEC+ decided to increase output in July by the same amount as it did in each of the prior two months, a relief to some who had feared an even bigger increase. [O/R]

Brent rose $1.07 to $63.85 a barrel, while U.S. crude gained $1.18 to $61.95 per barrel.