Five police officers have been arrested as part of an anti-corruption investigation which reportedly centres on allegations that statistics were manipulated to meet crime reduction targets.

Four men and a woman, detectives from Kent Police, were questioned on suspicion of persuading suspects to admit to offences they had not committed to boost their unit's performance statistics, The Times said.

The claims, involving a detective inspector, detective sergeant and three detective constables working in a group dealing with persistent offenders, are said to focus on the suspected handling of undetected crimes which are later labelled "taken into consideration".

A Kent Police spokesman said: "Five people arrested in Maidstone on Monday over allegations of administrative irregularities in the way prisoners had been dealt with have been released on police bail."

The officers have been suspended pending further inquiries into the allegations, the Kent Police Federation, which represents rank-and-file officers, confirmed.

Its chairman Ian Pointon said officers faced "enormous pressure" to meet performance targets and that failure to meet them can have a "detrimental effect on them personally".

He said the federation, which represents 3,500 men and women with Kent Police, is supporting the officers concerned.

He added: "Since 2006 we have highlighted the negative impact of this pressurised performance culture, a culture that is more about quantity than quality. Sadly our legitimate concerns have all too often fallen on deaf ears."

A spokesman for the Independent Police Complaints Commission (IPCC) said: "We have received a referral on the Kent matter and we are currently assessing it to determine our level of involvement."

Disclosure of the arrests comes on the day the public vote for the newly created role of police and crime commissioners, with many candidates vowing to drive down crime levels.