SINGAPORE - Nearly all employers have successfully filed their employees' CPF contribution returns.

A CPF Board spokesman said over 99 per cent of employers who use the online system have managed to submit their contributions as of Oct 15.

The spokesman said it is in contact with the rest of the affected employers on alternative arrangements.

The deadline to submit the CPF contribution returns is normally the 14th of every month.

But that deadline for the submission of September's returns was extended to Oct 17 after the CPF noted on its website that it was "experiencing some slowness with our Employer CPF e-Submission service".

The cause of the slowness in the system was not immediately clear, though The Straits Times understands that a hacking attack has been ruled out.

Zero Spot Laundry Service chief executive Alex Teo said his company, which hires 300 staff, has not been affected.

"So far, there has been no issue, I have not heard anything from my human resources department about the problem and we have been able to send our contributions on time."