(Bloomberg) -- Norway’s underlying inflation unexpectedly accelerated to a record-high pace last month, cementing expectations that the central bank will prolong its interest rate-hiking campaign beyond the summer.

Core inflation, the measure followed by Norges Bank, accelerated to 6.7% in May from a year earlier, compared with the 6.3% forecast by analysts in a Bloomberg survey and a central bank estimate of 6%. Headline inflation also quickened, defying forecasts of slowdown.

The data compounds the challenges faced by Norwegian households — the world’s most indebted — and the nation’s policymakers, who have been caught out by a weaker-than-expected krone that is fueling imported price growth. It will likely boost bets that Norges Bank will flag more rate hikes after the next expected increase later in June from the current level of 3.25%. Some forecasters see chances of a rate peak exceeding 4% later this year.

“After this figure, the risk that Norges Bank will have to raise rates above 4% has risen sharply and even the possibility for a 50 basis-point rate hike cannot fully be excluded at the June meeting,” Nordea Bank Abp’s analysts Dane Cekov and Kjetil Olsen said in a note to clients. “For now, we hold our view for a 25 basis-point rate hike in June.”

Investors now price a total of 83 basis points of additional hikes from Norges Bank, including 30 basis points for the forthcoming June meeting, 25 basis points for August and 22 basis points for September, according to Danske Bank A/S’s economist Frank Jullum.

The krone gained 0.8% to 11.6539 versus the euro at 10:14 a.m. in Oslo. It has been the biggest decliner this year versus both the dollar and the euro among the G-10 group of the world’s largest currencies.

The International Monetary Fund said on Thursday there are upside risks to Norwegian inflation, urging the government to refrain from fueling the price pressure caused by higher budget spending. That’s after the Labor-led cabinet said last month it would raise spending of its $1.4 trillion sovereign wealth fund, boosting the mainland economy by as much as 0.4 percentage points.

Read More: IMF Urges Norway’s Government to Avoid Fueling Price Pressure

Food and non-alcoholic drink prices jumped about 13% over the past 12 months, while transport costs rose 7.5%, the statistics office said, adding that price growth on imported goods also remains high, likely helped by the weak krone. Earlier on Friday, it released new forecasts showing core inflation will accelerate to 6% this year, compared with the previous forecast of 5.4%.

“It is not normal that food prices rise so much in May,” Sara Midtgaard, a senior economist with Svenska Handelsbanken AB, said in a note to clients, adding price pressure may persist for a long time. “This draws Norway’s Bank’s interest rate path clearly up and it’s at full speed toward an interest rate peak of 4%.”

--With assistance from Joel Rinneby and Stephen Treloar.

(Updates with food price jump, analyst comment from eighth paragraph.)

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