SAO PAULO (Dow Jones) - Soaring international sugar prices caused mixed reactions among Brazilian buyers and sellers this week.

Traders in Brazil -- the world´s top sugar producer -- are taking divergent views about to whether to buy or sell the commodity as prices surge even higher on concerns about tight global supplies.

March sugar on ICE was recently up 5%, or 1.52 cents, at 31.67 cents a pound, setting new 30-year highs.

"While some mills are taking the opportunity to sell sugar futures at high prices, others are waiting for even higher prices," Plinio Nastari, president of sugar and ethanol consultancy Datagro, told Dow Jones Newswires on Thursday.

Moreover, many analysts believe that world sugar prices still have room to rise further in the coming weeks on continued strong demand and concerns about drier-than-usual weather in Brazil´s  center-south sugarcane region, which accounts for 90% of the country´s cane.

However, although sugar prices may rise further in the coming weeks, they will remain very volatile, said Nastari, who specializes in sugar and ethanol in Sao Paulo.

In the physical spot market, mills are ending their crushing and have tight stocks. Nastari sees this tight supply reflected in the historically high sugar-export premiums.

Very-high-polarization raw sugar, known as VHP, this week is seeing premiums of 120-130 points over the March sugar contract on ICE.

Julio Borges, president of consultancy JOB Economia, said world sugar prices are almost double the average cost of production for mills in the center-south region.

"With these prices, they [mills] can see good profits," Borges said.

On the buyer side, importing countries and industrial buyers alike are nervously watching prices creep higher. "Buyers know that the prices are high," Borges said. "If possible, they will postpone buying."

-By Tony Danby, Dow Jones Newswires; 55-11-3544-7074; Anthony.Danby@dowjones.com