Big force fights out-of-control SA blaze

More than 100 firefighters and three aerial water bombers are battling an out-of-control bushfire near Port Lincoln in South Australia.

The SA Country Fire Service (CFS) says the fire, which is a risk to lives and homes, is burning at Sleaford Mere, west of Tulka.

It is travelling in a southerly direction towards Fishery Bay and is burning in scrub.

Residents are advised to take shelter when the fire arrives and to protect themselves from the fire's heat.

CFS state co-ordinator Malim Watts said the serious fire was "a weather driven event".

Strong northerly winds are expected to continue, before they abate a little and ease off.

"That might give us some respite in terms of being able to gain a bit more control over this fire," Mr Watts said.

"But then we are likely to see the winds turn to a more westerly flavour."

While it may then become cooler, the winds may be reasonably strong as well, so there was still some concern from a firefighting effort until the temperature decreases and the atmospheric moisture increases.

With 100-odd firefighters, other emergency workers, three aerial water bombing aircraft and an observation aircraft, the CFS was putting as much effort as possible into fighting the fire.

"At this stage our focus of attention is on asset protection and warning as much of the community that we believe are likely to be impacted as we can and making sure that others are aware of the situation as it develops," Mr Watts said.

He had no advice yet as to how the fire started, but said the CFS would work with police to investigate its cause.