Consumer sentiment in South Korea took a hard blow from Middle East Respiratory Syndrome in June, plunging to its lowest level in more than two years, amid growing concerns the outbreak will put a dent in Asia's fourth-largest economy, data showed Thursday.

South Korea is struggling to contain the outbreak of the acute respiratory illness that is the second-largest infection outside of Saudi Arabia. Since the first case was reported here on May 20, the death toll has climbed to 27.

The overall consumer sentiment index reached 99 in June, dropping below the benchmark level for the first time since December 2012 when it reached 98, according to the Bank of Korea. A reading below 100 indicates that pessimists outnumber optimists.

From a month earlier, the index fell by 6 points, falling more sharply compared with the 4-point drop in May 2014 when the country was grappling with the aftermath of the deadly Sewol ferry sinking.

"It seems that the MERS outbreak was one of the biggest factors that led to a contraction in consumer sentiment," said a central bank official.

The drop in consumer sentiment came amid escalating concerns that the outbreak will seriously hurt consumption and economic growth as consumers avoid public venues and foreigners cancel travel plans on fears of catching the illness.

Data by the state-run tourism agency showed that more than

120,000 foreigners have called off trips, while separate industry data showed that duty-free shops and department stores reported double-digit drops in sales.

Speaking to local economists on Wednesday, BOK Gov. Lee Ju-yeol said that while the pace of decline in consumption-related indicators has slowed since the outbreak's initial stages, economic uncertainties are expected to persist for a considerable period.

In effort to prop up sentiment, the BOK slashed the policy rate to a record low of 1.5 percent on June 11. Seoul has also unveiled measures to support MERS-hit sectors, such as drawing up funds for soft loans and delaying tax audit schedules.

Nonetheless, economists forecast the unprecedented outbreak will further cut growth here, bolstering the case for a supplementary budget. Nomura projected MERS to drag down growth by .3 percentage point, while the Korea Institute of Finance expected a 0.1 percentage point dip.

On Wednesday, ruling party floor leader Yoo Seung-min told reporters that the government will form a supplementary budget of over 10 trillion won ($9 billion), with 5 trillion won of the total to be used to make up for tax deficits while the remaining amount will be put aside for extra spending.

The CSI survey of 2,200 households across the country was conducted between June 11 and 18. (Yonhap)