Chocolate prices may start rising in 2013 as the price of cocoa butter, the special ingredient that gives chocolate its delectable melt-in-your-mouth texture, nearly doubles, Reuters reports.

Some smaller chocolate makers have already pushed up prices.

"We have increased our chocolate prices by 30 to 40 percent since January and most of our customers are not happy about it," said Richard Lee, chief executive officer of Aalst Chocolate, a Singapore-based chocolatier that sells chocolate to bakeries, ice cream makers and food manufacturers, Reuters reports.

"With the festive season just around the corner, the price of (cocoa butter) will rise even further and surely hit the bottom line of chocolate makers," he said.

According to the report, increased demand from Asia's expanding middle class and a turnaround in sales in big consuming countries have seen butter prices nearly double to more than $7,000 a tonne from $4,000 a tonne six months ago.

With an expected increase in demand as the year approaches the 2013 Christmas and New Year period, as well as supplies tightening, some chocolate makers may have little choice but to pass on the increased costs to consumers, Reuters reports.

But major sweet makers contacted by Reuters declined to comment on whether the rising price of cocoa butter would lead them to raise the retail price for their chocolate bars.

Nestle did say any increase in price is always the last resort.

Around the globe, chocolate is gaining more and more lovers. According to Reuters, about 7.4 million tonnes of chocolate will be consumed in 2013, up nearly 2 percent from last year, and worth about $110 billion, according to global market researcher Euromonitor International.

"In the regions like Asia-Pacific or Latin America, we are seeing more middle class consumers buying chocolates compared with five or six years ago because they have the money to do it," Francisco Redruello, senior food analyst at Euromonitor International, told Reuters.

"That is what's driven the growth of chocolates."

Sales also normally surge in Europe and North America around Christmas, Valentine's Day and Easter, putting pressure on confectionery companies to stock up.