A 60-year-old pharmacy worker has been left with a broken finger and stressed after a rough sleeper attacked her in her central city workplace.

Jessica* was also disappointed by the emergency response at a time police say they are beefing up foot patrols in the city, and the Christchurch City Council prepares to fund "outreach" social workers.

Officers took 17 minutes to arrive after Jessica was assaulted at Cosmo Pharmacy in Colombo St, central Christchurch, about 160 metres from the central police station. Police have defended their response, saying they were told the assailant had already left – then found and arrested the man in less than 90 minutes.

Jessica was working in the store last month when a large man entered late in the day.

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After she tried to help him with a muddled request, he head-butted her with moderate force, hurting her nose, cheek and pushing her glasses off her face. The man pushed her several times while she and a colleague tried to get him to leave.

"He walked up and he shoved me in the chest, straight back onto the wall ... By that time [a colleague] was right beside me and we were screaming at him to get out," she said.

ALDEN WILLIAMS/STUFF Jessica's finger was broken in the attack as she held her hands up in defence.

Then the man "up-ended" the slim, 1.5m-tall woman onto the floor, where she landed between a counter and some cupboards.

She held her hands up in self-defence. As one of the blows came down it broke her finger – an injury a doctor later described as one suffered mostly by cricketers attempting to catch a fast ball.

After what "felt like an hour", she managed to squirm out of the way and escape. The man left the store before police arrived.

ALDEN WILLIAMS/STUFF Jessica has been diagnosed with PTSD and struggles to think about what happened to her.

This week she was diagnosed with post-traumatic stress disorder. Jessica breaks down when she recalls the assault and what it has done to her mental wellbeing. She asks not to be identified due to the fear of another attack.

"This is what gets me. I'm always the strong one ... so to get reduced to this is new for me," she said through tears.

Canterbury Metro Commander Superintendent Lane Todd said police went to the scene but the man had fled. Officers found him about 5.40pm the same day, arrested and charged him with male assaults female.

He appeared in the Christchurch District Court the following day and had been remanded in custody since. He was due to reappear on July 31.

Todd defended the police response time, and said officers were called at 4.05pm on the day of the assault and told the man was heading for the bus interchange on Lichfield St. They arrived at 4.22pm.

"Police prioritise attendance at events based on a number of factors, such as the seriousness of the individual circumstances, vulnerability of the people involved [and] potential for the incident to escalate.

"It's important to remember that police are mobile and may not always be deployed from a police station ... in general, the closest free unit to an address will be deployed to ensure a timely response."

ALDEN WILLIAMS/STUFF Rough sleepers cause issues outside Cosmo Pharmacy at least once a week, Jessica says.

Todd said police were working with the council and other agencies regarding reports of anti-social behaviour in the CBD.

Earlier this week, police announced they would increase the number of foot patrols in the city centre within the next three-to-six months, in a bid to curb anti-social behaviour.

A multi-agency street count last year tallied 215 people sleeping rough in central Christchurch, a number many believe is growing.

On Thursday, all city councillors approved to fund $70,000 for one full-time-equivalent "outreach social worker" to contribute to the effort over 12 months.

The Christchurch City Mission would fund another, and councillors requested a review after about six months into the plan to measure its effectiveness.

At Thursday's meeting, Councillor Anne Galloway said the need for the funding became "urgent" as agencies heard "more and more incidences of people feeling unsafe" in the city centre.

ALDEN WILLIAMS/STUFF Jessica thinks the increased police and social worker presence will do little to solve the issues caused by some of the city's rough sleepers.

The biggest impact on Jessica came two days after she tried to return to work.

She woke in the middle of the night in pain and barely able to move. A relative rushed her to the hospital where she was told she had suffered a spontaneous coronary artery dissection (SCAD) – a type of heart attack.

"Beyond the physical injuries, this has undoubtedly caused her significant emotional stress," a cardiologist wrote about Jessica.

"SCAD has been shown to be associated with emotional stress ... I am highly suspicious that this lady's ordeal was associated with her SCAD."

*Name changed.