$20 oil 'is still possible': Gartman

The recent rebound in oil should not be seen as a sign that the price has reached a bottom, influential investor Dennis Gartman told CNBC Tuesday, warning that $20 per barrel was "still possible."

"I actually doubt that we have (hit a bottom) what we've seen in the past week and a half or two weeks is a substantive rally from the lows but what is depressive to me is the fact that the carrying charge has not done what one would want to see the carrying charge do in a rally," Gartman, the author of the "Gartman Letter" told CNBC's "Worldwide Exchange" Tuesday.

"We've seen the market continue to have a large contango (where people are willing to pay more for a commodity at some point in the future than the actual expected price of the commodity) and crude continues to bid for storage," Gartman said.

Gartman illustrated his point with a reference to the oil storage hub in Cushing in Oklahoma where an estimated 2.3 million barrels of oil is stored in tanks, according to oil service company Genscape, and "huge numbers of ships out on the water" also being used to stockpile oil.

"In that environment it's very hard to think that this is anything more than a much-needed technical bounce and any further $1 or $2 rally in crude oil probably should be sold. I think the lows have not yet been seen and maybe $20 a barrel is still possible."

Gartman's comments come after Citigroup published a report on Monday stating that oil prices – which have fallen 50 percent from around $114 per barrel last June to currently trade around $57 – could fall as low as $20 per barrel .

"It's impossible to call a bottom point, which could, as a result of oversupply and the economics of storage, fall well below $40 a barrel for WTI, perhaps as low as the $20 range for a while," Citi's head of global commodities research Edward Morse said in the report Monday. "The recent rally in crude prices looks more like a head-fake than a sustainable turning point."

The comments come amid a number of reports that signal a slow recovery in oil markets. On Tuesday, the International Energy Agency said that while the rebound in prices of late showed there was "light at the end of the tunnel," it "could take years" for the market to rebalance.

- By CNBC's Holly Ellyatt, follow her on Twitter @HollyEllyatt. Follow us on Twitter: @CNBCWorld