Small businesses owners have been reminded that electronic payroll filing will be compulsory for all companies from 2009-10.

HM Revenue & Customs (HMRC) will require all employers to file their P35 and P14 year-end tax and national insurance documents online.

According to software supplier IRIS many businesses are unprepared for this change and consequently has issued a guide to the HMRC requirements.

"Until now, organisations with fewer than 50 employees have been free to file their returns using a number of methods," said Oliver Shaw, IRIS managing director.

"Larger organisations have been compelled to file electronically since 2005; however, new regulations make electronic filing compulsory for all businesses from the end of this fiscal year."