Australian entertainer Rolf Harris has had his bail extended by British police in relation to his arrest on suspicion of sexual offences.

The 83-year-old has still not been charged with any offence, but he was required to report to police as a routine part of their ongoing investigation.

He is still under arrest and is now scheduled to report to police again in early August.

British investigators say the allegations against Harris relate to historical sexual offences, but have not released any further details.

Harris has not commented about any of the allegations, but thanked his fans for their support when he performed a live show over the weekend.