The union representing the City of London's inside workers says hiring replacement workers and encouraging scabs won't end the strike.

CUPE Local 101 is also disputing claims that 20 unionized workers have crossed the picket line and returned to work, but admits that a couple of members have broken ranks - with the knowledge they could face serious consequences.

As week five of the strike by 750 workers got underway, London Mayor Matt Brown confirmed council knew private contractors were being brought in to help city departments cope.

"Council is aware there are under 20 individuals providing services in the Ontario Works area, in the IT area and the development area focussed on permits," Brown said Monday night.

But when it comes to union members, CUPE Local 101 president Shelley Navarroli says, "I'm aware of two with a potential of two more. That number is primarily the students who have gone back in so they don't lose their co-op credit."

She believes the city's number is inflated by including temporary summer co-op students who are stuck in the middle of the dispute.

In a statement also released Monday, Navarroli expressed anger over the mixed messages coming from city hall.

"While Mayor Brown makes blanket statements of 'valuing city workers', it appears the City Manager is doing quite the opposite of what the mayor is saying publicly...Hiring replacement workers and openly encouraging scabs are certainly not valuing or showing respect to our members."

Still, Brown says he stands by the decision made by Art Zuidema, as the city needs to "continue to focus on services for our most vulnerable, we have to stay focussed on our local economy."

But in a message to union members, Navarroli outlines the consequences permanent workers could face for crossing the picket line.

It reads in part, "A trial committee of union members may impose penalties for these offenses, including fines or even suspension from membership in the union. Under the expired collective agreement, maintaining membership in Local 101 is a mandatory requirement for all of us."

She adds that being a member of the union is a condition of employment, and they will "pursue all avenues open to us for members who choose to cross the picket line while we are on strike."

But Rob Paynter, director of communications for the City of London, says the city believes the Labour Relations Act protects employees from being fired if the union suspends or expels them.

He adds the city will require a settlement with the union guaranteeing no union reprisals can be taken against members who cross the picket line.

Financial pressures may be part of the reason the union is trying to get the city back to the bargaining table.

Walking the picket line for 20 hours a week, CUPE members are earning $300 in strike pay, that's about a quarter of the average member's gross pay under the previous contract.

Outstanding issues in the contract dispute include wages, early retirement benefits for new employees, expanded work hours and changes to job evaluation and promotion policies.