Locked out call-centre staff used a D-lock and a truck to lock managers and some non-union staff inside.

When Synovate workers arrived on Saturday morning they found the front door to the transnational market research company locked.

Unite union organiser Omar Hamed said workers decided to use locks of their own.

When asked what would have happened if there had been a fire, Mr Hamed said, had they heard an alarm, they would have let the people out.

The lock-out continues today and workers have turned their attention to the clients of the call centre.

Mr Hamed said workers had picketed ASB Bank and the Ministry of Social Development and been moved on by police.

When nzherald.co.nz phoned, Mr Hamed was with workers at AMI Insurance's head office this afternoon asking managers for a letter of support.

The 24 union members have been locked out for four days, after refusing to take either the offered 20c pay rise or pull out of the union, Mr Hamed said.

The telephone interviewers were asking for a 50c-an-hour pay rise, which would take their wage to about 4 per cent above the minimum wage level, Mr Hamed said.

They also wanted 12 hours' notice of roster changes, rather than finding out they were not working after arriving at work.

Mr Hamed said the union workers will receive financial support from other unions in Australia and New Zealand.

"They're not rich people by any stretch of the imagination."

But Synovate managing director Ian Mills said the union members had already been offered a 3 per cent pay rise, and with added performance bonuses would easily equal the 4 per cent wanted by union negotiators.

Two carloads of Unite union members had come to his house at 6.30am yesterday, shouting messages into megaphones about him being a sinner, he said. Mr Mills said the action had traumatised his children.

His company was struggling to keep jobs in New Zealand, and at least three other call centres in Auckland had recently closed with the loss of more than 600 jobs.

In total, Synovate employed about 200 people, he said.