By Steve Scherer and David Ljunggren

OTTAWA, Sept 19 The Bank of Canada on Tuesday said recent volatility in headline inflation is not unusual but the underlying trend shown by core measures was inconsistent with bringing inflation down to the 2% target.

Earlier on Tuesday, August inflation figures showed a jump in the headline number to 4.0% from 3.3% in July, higher than most analysts had forecast.

"Ups and downs of the size we've seen in the past couple of months are not that unusual," Deputy Governor Sharon Kozicki said in a speech at the University of Regina in Saskatchewan.

"(They) are one reason why we look at measures of core inflation - which exclude components with more volatile price movements - to get a sense of what underlying inflation is."

One of those core measures, CPI-trim - which leaves out spiking mortgage interest costs - has been between 3.5%-4% in recent months.

"Underlying inflation is still well above the level that would be consistent with achieving our target of 2% CPI inflation," Kozicki said.

After the August inflation data were released, money markets raised bets for a rate hike after the next policy meeting on Oct. 25, seeing a 42% chance of an increase compared with 23% before.

Inflation has exceeded the bank's 2% target for more than two years.

Bank of Canada Governor Tiff Macklem said on Sept 7 that interest rates may not be high enough to bring inflation back down to target even after 10 hikes of a total of 475 basis points since March of last year.

The Bank of Canada kept its key rate at 5% on Sept 6, noting the economy had entered a period of weaker growth, but said it could hike again should price pressures persist.

In her speech, Kozicki also said that while there is evidence that previous rate hikes are slowing demand, inflation remains too high, "and that tends to mean that real interest rates need to remain high".

(Reporting by Steve Scherer, editing by David Ljunggren)

((Reuters Ottawa bureau, david.ljunggren@tr.com))

Keywords: CANADA CENBANK/