Stock guru Jeremy Siegel, professor of finance at the University of Pennsylvania, has been bullish on the market throughout its six-year rally and remains that way.

But a correction could be in store if the Federal Reserve raises interest rates in June, as many experts expect, he tells CNBC. "It's the first time I've been cautious in a while."

To be sure, Siegel doesn't think the Fed should move in June, given "poor" economic growth and miniscule inflation. "I personally think it would be premature in June."

Fourth-quarter GDP growth was revised down to 2.2 percent last month from 2.6 percent previously. The economy expanded 5 percent in the third quarter. Consumer prices slipped 0.1 percent in the 12 months through January, the first 12-month decline since October 2009.

"If we're going to get a June rise, there are going to be some ripples in the stock market before this is over," he predicts. "I certainly would not be surprised to see a correction in the next three months that brings the market, down maybe 5 percent to 10 percent."

However, Siegel still sees 20,000 as fair value for the Dow, but "it may not get there in 10 months."

"On a historical basis, the current price-earnings ratio is above the historical average. The reason I'm not bearish is that interest rates are so low," he notes. "Even with the Fed maybe tightening in June, maybe September, they are going to remain well below their average for many, many years."

Siegel believes stocks are the place to be. "I would not advocate to start tilting away for stocks and moving into alternative assets. I don't see any there that I find more attractive than stocks at the current time."

Hedge fund manager Doug Kass, president of Seabreeze Partners Management, doesn't share Siegel's underlying bullishness.

"My market view remains negative, and I am positioned defensively," he writes on his blog. "Thus far, the market is indifferent to what I have seen as a deterioration in the macroeconomic trends and to rising geopolitical threats."

Traders and investors have pushed stocks higher, "despite a material decline in corporate profit expectations (caused by lower oil prices, a stronger U.S. dollar and slowing global growth)."
Analysts predict profits will fall 4.9 percent in the current quarter, according to Bloomberg.

In addition, "sentiment is elevated, as the bull market in complacency has hit a new high, and many of the most important valuation methodologies are seriously stretched.

Related Stories:

• Insana: February Employment Report Was No 'Snow Job'
• Sean Hyman: Fed Rate Hikes Aren't 'Something to Be Feared'