Utility companies could be facing a hacking time bomb owing to poor security measures.

As more utilities move control and billing systems online an analyst has warned that hackers are increasingly turning their attention to the possibilities of controlling the systems.

While there is little direct financial benefit in breaking into such systems, there may be other benefits.

"The utility companies are moving to completely digital systems and security is not prioritised," said Fran Howarth, partner at analyst firm Hurwitz & Associates.

"Hackers could siphon off electricity for use in projects like indoor drug farms, for example, and charge it to consumers.

"The problem is that 80 to 90 per cent of the critical infrastructure is in private hands and they have their own security problems, so consumers are low down on the list."

Howarth warned that some critical infrastructure owners are even neglecting physical security, particularly in the US.

The increase in political hacking means that companies that own sections of critical infrastructure need to be aware of the need for greater security infrastructure.