One editor has been called into Kent police offices and warned that he faces prosecution if his newspaper continues to publish offensive material. The offence carries a maximum two-year jail term.
Detectives are compiling evidence from several other publications and intend to issue further warnings to their editors.
The move follows complaints from several people including the Dover MP, Gwyn Prosser, and a solicitor who believe the newspapers are breaking the law and press guidelines.
Kent police yesterday took the unusual step of criticising local and national newspapers for their coverage of the immigration issue, particularly recent reports about asylum-seekers arriving in Dover, Folkestone, Gravesend and Dartford.
A force spokesman described some of the reports as "inflammatory" and "unacceptable". He blamed them for heightening tensions and attracting far-right groups, such as the National Front.
Earlier this month, Kent police warned Nick Hudson, group editor of a number of weekly newspapers including the Folkestone Herald and Dover Express, that he risked being charged with inciting racial hatred.
Among the articles published in October in the Dover Express was an editorial headed "We want to wash dross down drain". It said: "Illegal immigrants, asylum-seekers, bootleggers ... and scum of the earth drug smugglers have targeted our beloved coastline ... we are left with the backdraft of a nation's human sewage and no cash to wash it down the drain."
In a story under the headline "DSS cheats are now into brothels" in October, about a campaign against the asylum-seekers, it quoted a woman saying: "The police are called out up to 15 times a day because of immigrants shoplifting. And at least three brothels have popped up around Dover."
Mr Hudson, who worked on the Daily Sport and Sunday Sport, said: "I'm merely reflecting my mailbag. I don't think we are making the news, we are merely reflecting it."
A spokesman for Kent police said: "There has been a lot of inflammatory coverage which has raised tensions among communities and attracted members of far-right organisations, which is something which concerns us greatly."
Among the incidents to provoke a flurry of negative articles - most noticeably in The Sun and the Daily Mail - was the discovery several weeks ago of 103 Romanian men, women and children hiding in the back of a lorry in Dartford.
Five days ago, the door of a house in Dover where two Slovakian refugees had been staying was set alight in a suspected race attack.
Following the articles on the Romanians, police had to deploy extra officers to give them protection.
Mr Prosser, a Labour MP, said: "One of the local newspapers in recent months took a most hostile view on the asylum and immigration problem. It added to the difficulties in Dover and inflamed an already difficult situation."