SINGAPORE - The local stock market retreated on Thursday amid concerns over Greece's debt and a deepening economic slowdown in China.

The benchmark Straits Times Index fell 10.99 points or 0.3 per cent to 3,406.58, erasing gains it had made on Wednesday.

Most other regional markets were also weighed down by the European Central Bank's decision on Wednesday night to toughen its stance on Greece.

The ECB said that it would no longer accept Greece's junk-rated government bonds as collateral in return for ECB funding to Greek banks, in a move that some analysts say raises risks for a Greek exit from the euro zone.

Although Hong Kong was up 0.4 per cent, Tokyo fell 1 per cent and Seoul shed 0.5 per cent. Shanghai tumbled 1.2 per cent.

"There is increasing fear that Greece may leave the (European) Union if European leaders are not able to come to an agreement on Greece's debt restructuring," Phillip Futures analyst Howie Lee said.

However, he added that the new left-wing Greek government would likely not be "held to ransom. No one wins at the end of the day if Greece leaves".

In Singapore, the most active stock was Pacific Andes, which inched up 0.1 cents to 5.8 cents on 66.2 million shares traded.

There were 989.4 million shares worth $1.05 billion in total traded, with the 139 gainers outnumbered by the 229 losers.