FTSE said real-time indexes had been affected by a 'disruption' and that it was investigating the extent of the problem.

'We will advise as soon as the disruption has been sorted out,' Meredith Blakemore, a Hong Kong-based FTSE spokeswoman, said by phone.

Ms Blakemore said FSTE calculates and disseminates the Straits Times index for the Singapore Exchange. Those operations are carried out in London, she said.