By Tom Fairless 

SINTRA, Portugal--European Central Bank President Mario Draghi urged major central banks to better coordinate their policies to tackle the shared problem of ultralow inflation in his first major speech since Britain voted to exit the European Union.

The comments, to an ECB conference in Portugal, indicate a shift in emphasis for the eurozone's central bank, which had until recently stressed its ability to hit its near-2% inflation target regardless of the side-effects of its policy measures.

Addressing an audience of policymakers and academics, Mr. Draghi said central banks should think about whether their policies are "properly aligned" with those of their peers. He warned that currency devaluations aimed at boosting competitiveness are a "lose-lose" for the global economy."

"In a globalized world, the global policy mix matters--and will likely matter more as our economies become more integrated," Mr. Draghi said. "The speed with which monetary policy can achieve domestic goals inevitably becomes more dependent on others."

The remarks indicate a "definite shift" in Mr. Draghi's thinking, said Frederik Ducrozet, senior economist with Banque Pictet & Cie SA in Geneva.

"It suggests that the ECB is increasingly concerned about those 'global factors' driving inflation that they cannot directly influence," Mr. Ducrozet said.

The ECB has missed its inflation target for three straight years, despite repeatedly expanding its bond-purchase program in recent months and cutting interest rates further below zero. In a speech in February, Mr. Draghi said neither global economic forces nor the risk of side-effects would prevent the ECB from hitting its inflation goal.

Investors are increasingly concerned that the central bank is running out of tools to support the eurozone economy and drive up inflation.

"I think the ECB does not have a lot of ammunition left, at least a lot that would really make a difference," said Martin Lueck, chief German investment strategist at BlackRock, Inc., which manages assets worth $4.7 trillion.

Those concerns have been aggravated by the fresh economic headwinds emanating from across the English Channel, after Britons voted last week to leave the EU. European banks have come under renewed pressure in the wake of that vote, a worry for the ECB because banks help transmit the central bank's policies to consumers and businesses.

A key benchmark, the Stoxx 600 Europe banks index, has fallen to its lowest level since the summer of 2012, when the eurozone debt crisis was at its height and Mr. Draghi declared the ECB would do "whatever it takes" to save the euro.

Speaking at the same event in Portugal, ECB executive board member Benoît Coeuré described the U.K. vote as a "major shock". Mr. Draghi didn't address the issue in his speech, but over dinner on Monday evening, he expressed "sadness" about the referendum result.

In his speech, Mr. Draghi spoke of "persistent headwinds" from overseas that have forced central banks to use their policy tools with ever more intensity, resulting in "higher financial stability risks and spillovers to economic and financial conditions in other jurisdictions."

He said central banks "can always achieve [their] objective eventually." But he said they could do so "faster, and with less collateral effects, if the overall policy mix is consistent."

Analysts speculate that the ECB may be forced to boost its stimulus again later this year to support the region's economy and ease conditions in financial markets. Such a move might come after the central bank unveils its new economic forecasts in September.

The ECB accelerated its purchases of corporate bonds last week to EUR2.65 billion ($2.92 billion) from around EUR1.9 billion the previous week, according to ECB data, a much faster rate than analysts had forecast. Bankers said the acceleration might partly reflect an effort to front-load the program before the summer trading lull.

Britain's unexpected referendum result comes at a particularly awkward time for the ECB, as the central bank's top officials had recently expressed confidence that they were nearing their inflation objective.

Write to Tom Fairless at tom.fairless@wsj.com

(END) Dow Jones Newswires

June 28, 2016 08:37 ET (12:37 GMT)