The workers were locked out of the council's Stafford depot at 12.01am on Sunday, according to the Electrical Trades Union, following industrial action undertaken by the workers on Friday, which aimed to have their claims heard during enterprise bargaining negotiations.

In a sign of at least some state government support of the workers, State Development Minister Anthony Lynham joined them outside the depot in his electorate on Monday morning.

ETU organiser Brenton Muller said the council's response to a day of what he called "minor" action could potentially put public safety at risk.

"Now Brisbane City Council have locked out these workers, they will be unable to provide any emergency response to problems on the city's traffic signal network," he said.

"If traffic lights go out with these workers locked out, they won't be available to fix them and you can imagine the traffic chaos that will cause."

The workers had taken part in paperwork bans, along with bans on "minor" tasks, in response to the council's new "flexible rostering" proposal, which the ETU said would allow the council to force workers on shifts with limited notice.

"These electricians are already flexible and work when they are needed to, but council is trying to pass a condition that they can dictate when they have to work 24/7 with zero consultation," Mr Muller said.

"The actions of Brisbane City Council during these negotiations are reprehensible to say the least.

"It is hard to see who council have less respect for, their workers or the Brisbane public."

Australian Manufacturing Workers Union Queensland and Northern Territory secretary Rohan Webb said his union was working towards having its members take protected industrial action.

Mr Webb said the lockout of workers was "callous and below the belt".

"This is a heartless and disproportionate decision from a council that clearly doesn't care about BCC workers or their families," he said.

"The proposed rosters are a joke. These rosters mean that employees won't be able to plan a trip with their families because they will constantly be on call."

A council spokeswoman refuted the unions' claims that staff had been locked out and said arrangements had been made to ensure operations continued without any effect on public safety.

"The electricians involved in the industrial action were advised that they would not be rostered on for the duration of the action, so that council could ensure there is no impact to public safety," she said.

The spokeswoman said enterprise bargaining negotiations had been underway since last October and the council was "committed to delivering a fair outcome for all employees".

"These discussions are continuing," she said.