The consumer price index (CPI), the key measure of inflation, is believed to have increased in the June quarter by 1 per cent for an annual rate of 3.4 per cent, an AAP survey of 11 economists shows.

4Cast Financial Markets head of research Ray Attrill had expected the central bank to raise the cash rate from 4.5 per cent to 4.75 per cent if inflation comes in evidently high.

"The case has to be unequivocal, because of the election," Mr Attrill said.

The minutes of the Reserve Bank's July board meeting implied there could be an interest rate hike in August if official inflation data showed higher than expected.

An increase in inflation may also result from the federal government's April move to lift the cigarette excise by 25 per cent, according to predictions of the central bank's staff and several economists.

There are also rising fears about the global economy, emphasised by US Federal Reserve chairman Ben Bernanke's congressional testimony that the outlook for the American economic growth seems "unusually uncertain".

Additionally, market observers, including the Reserve Bank, are concerned over the strength of European economies and banks as they wind their way out of the debt crisis.

"When I think of Bernanke's comments, that's given the RBA some wriggle room and, given the RBA has stressed the risks to Asian growth from a slowdown in the US, I think that offers a pretext to duck an unusually high inflation print next week," Mr Attrill said.

"I think it would be a fine line."

Nomura Australia chief economist Stephen Roberts had expected the CPI data to be a mixed bag, with only slight price increases in food and housing, but large hikes in tobacco and alcohol.

However, he said the central bank was still likely to lift the cash rate in August as a "stitch in time" process, whether the underlying inflation rate comes in below 3 per cent year on year.

"As we go out from the second quarter, the problem is whatever we see now, with a little bit of to-ing and fro-ing over the second part of this year, this is the base we're going to grow on, not contract on," Mr Roberts said.

"There's a problem for the Reserve Bank."

Mr Roberts said he predicted the cash rate to reach 5.25 per cent over the next nine to 12 months.

But he believes the Reserve Bank may become heavily reliant on quarterly CPI results over that interval.

"I think they will next pause for an extended period of time when we get to 5.25 per cent," he said.

"It maybe will take three CPI prints to get there, though."