The Federal Reserve is expected to hike interest rates another quarter point today. But after 18 months in which the Fed has been pushing rates higher to keep inflation under control, the central bank appears to be getting close to the end of its rate increase campaign.

However, there is a divergence of opinion among economists on just when the rate increases will cease. One group thinks the Fed will stop after two more rate increases, while analysts who are more worried about inflation think the central bank could raise rates perhaps four more times.

There is no dispute, however, over what Federal Reserve Chairman Alan Greenspan and his colleagues will do at Tuesday's meeting. Expections are essentially universal that the Fed will increase the funds rate, the interest that banks charge each other, by a quarter point to 4.25 percent, the highest level since May 2001.

It would mark the 13th time the Fed has raised interest rates since it began tightening credit in June 2004 when the funds rate stood at a 46-year low of 1 percent.

"Another quarter-point rate hike is baked in the cake," said David Jones, chief economist at DMJ Advisors, a Colorado-based consulting firm. "But we are near the end."

Jones is in the camp that believes the Fed will boost the funds rate at Tuesday's meeting and then deliver one more quarter-point increase at Greenspan's final meeting on Jan. 31, leaving the funds rate at 4.5 percent.

But other economists argue that inflation pressures spawned by a surge in energy costs this year will prompt the central bank to keep pushing rates higher even after Greenspan leaves office.

They also believe that Ben Bernanke, who has been nominated by President Bush to succeed Greenspan, will want to quickly demonstrate his own inflation-fighting credentials.

For that reason, they are looking for Bernanke to keep pushing rates higher in small quarter-point increments at his first Fed meeting as chairman on March 28 and possibly a final move at the May 10 meeting.

That would leave the funds rate at 5 percent, a level that some economists believe the central bank may feel is needed to make sure that interest-rate sensitive sectors of the economy such as housing slow enough to keep inflation under control.

"The Fed is looking at an economy right now that is growing strongly with upside risks to inflation," said Lyle Gramley, a former Fed board member and currently senior economic adviser at Schwab Washington Research Group, a financial advisory firm.

Indeed, a variety of recent statistics have come in stronger than expected, depicting an economy that is rebounding after the blows delivered by a string of devastating hurricanes and a spike in energy prices.

Hints about the Fed's future intentions may come from the wording of Tuesday's statement explaining its latest action.

For all of the rate increases so far, that statement has said future increases will occur at a "pace that is likely to be measured," a phrase seen as a signal of quarter-point increases.

The statement has also described current policy as still accommodative, meaning interest rates are still low enough to spur economic growth. The Fed's goal has been to raise rates to a neutral level which is neither spurring growth nor holding it back.

The minutes of the Fed's last meeting on Nov. 1 showed that policymakers were discussing how the language should be changed, but some economists think that debate may go on a little longer before a consensus is reached.

"I think they are struggling with how to let markets know the rate hikes are coming to an end," said David Wyss, chief economist at Standard & Poor's in New York. "The problem is that anything they say will get over-interpreted by financial markets."

For that reason, some analysts think they may leave the wording unchanged at Tuesday's meeting and only change it when they actually have reached the end of the current rate increases sometime next year.