Police are investigating three aggravated robberies that have occurred in Christchurch in the last week.

Last Monday, four people stormed Riccarton Liquorland - one armed with a hammer - stealing cash, cigarettes and alcohol.

On Saturday three men, two armed with hammers, entered Ferry Road's Night and Day and stole cigarettes.

Later that same day, three men smashed their way through Woodham Road Liquor Store's locked doors.

Detective sergeant Brad Greenstreet says there's nothing showing the robberies were linked, but victims are shaken.

He says they're after any information from the public on the incidents.

Police are alsostill searching for a man after a service station stabbing in Christchurch.

An altercation broke out on the corner of Edgeware Road and Cranford Street around 6.30 on Sunday morning.

One person was taken to hospital in a serious but stable condition.

A police spokesman says they are yet to make any arrests.