Employers are urging independent senator Jacqui Lambie to support the government's union-busting legislation, regardless of whether John Setka resigns - saying the bill is "not about" the controversial CFMMEU Victorian construction branch secretary.

Senator Lambie has cemented her position this week that she will support the industrial relations bill if Setka does not step down as secretary of the union's Victorian construction division, urging him to resign for the sake of the 1.4 million union members who will be affected.

Jacqui Lambie says she will support the union-busting bill if John Setka resigns from the CFMMEU. Credit:Alex Ellinghausen

"You are doing more damage than good and it is time for you to go," Senator Lambie declared.

Australian Council of Trade Unions secretary Sally McManus is understood to be continuing to lobby Setka to stand down for the sake of the union movement, sparking employer fears that the bill - which would make it easier to deregister law-breaking unions and ban officials - may be defeated.