CityCat crews will strike again for 24 hours from Friday morning as unions argue the company running the CityCats for Brisbane City Council is replacing permanent staff with casual staff.

The company, Transdev, insists this is incorrect and the core issue is the scale of the wage increase.

It is the third strike by CityCat crews against Transdev since December 2018 as the unions continue their 12-month struggle to renegotiate the enterprise bargaining agreement with the company.