THE Singapore Exchange said on Thursday that the key Straits Times Index was not reflecting the movement in its component stocks.

'Market participants are advised not to rely on the figure until further notice,' the Exchange said. 'Market makers for Structured Warrants on Straits Times Index may not be quoting on those issues.'

The technical problem started on Wednesday morning which the Exchange attributed to an isolated computational error.

'The index was 3,376.06 at the noon trading break, when it should have been 3,437.36, which was a difference of 1.27 per cent,' the exchange said in a statement late on Wednesday.

However the problem was resolved by the afternoon, with the index correctly reflected the prices of its components from the start of second trading session.

Traders said on Thursday morning that the index was not accurately reflecting its closing level for the previous trading session.

The latest problems at Singapore Exchange come after Singapore traders had reported technical problems such as delays in prices and trade executions on Aug 17, a day of particularly heavy trading and share price volatility as fears of a global credit market squeeze mounted.

SGX in February halted its derivatives trading system for several hours after it encountered technical problems. Since then there have been a few other incidents.

In March, traders had problems accessing its ageing Singapore Exchange Securities Order Processing System, or Sesops.