Readers will be aware that the Government has proposed several changes to the Employment Relations Act - changes which have aroused the ire of the unions.

Council of Trade Unions (CTU) president Helen Kelly has called for select committee hearings throughout the country. Despite submissions on the changes closing on July 25, the CTU plans to embark on several months of campaigning, including nationwide rallies.

The unions are particularly passionate about protecting collective bargaining because it goes to the heart of trade unionism. Unions organise and get membership through successful collective bargaining.

If the bargaining process becomes anaemic, it will be much harder for unions to sign up new members. The fewer members the unions have, the weaker their bargaining position becomes.

The very essence of a union is the uniting of workers to achieve a common objective. The changes proposed by National that affect that have, not surprisingly, drawn the sharpest response.

So what are the changes, exactly?

The most important change curtails the ability of unions to secure an agreement in collective bargaining.

When Labour introduced the Employment Relations Act in 2000, it included a measure of protection for collective bargaining. However, it was Labour's 2004 amendment that really gave unions teeth. Essentially, the amendment required that bargaining had to be concluded unless there was a genuine reason, based on reasonable grounds, not to.

The proposed changes will still require parties to bargain in good faith but that will not require them to conclude collective bargaining. While employers cannot simply walk away, under the new law they can ask the Employment Relations Authority to let them end bargaining, if there is a stalemate. However, the authority must consider whether the parties have explored all appropriate dispute resolution avenues.

Second, the Government wants to change the law relating to Mecas (multi-employer collective agreements). Currently, employers given notice by a union of an intention to bargain for a Meca are obliged to bargain. This means that unions can try to get an agreement that covers all institutions within a certain industry across the country. For example, a union might try to get an agreement to cover all public hospitals in New Zealand.

National's proposed change will allow employers to opt out of bargaining for a Meca from the outset. Returning to the hospital example, if the Nelson Marlborough District Health Board wanted its own agreement, then it would be able to opt out of the Meca and focus on negotiating separately with the union for its own workers.

Completing the trifecta is the removal of the 30-day rule. The present rule requires that new employees be employed on terms and conditions of an applicable collective agreement for the first 30 days of their employment. After the 30 days have expired, the employee has the option of either joining the union and staying on the collective agreement or, alternatively, opting out and negotiating a separate, individual agreement.

The 30-day rule helps union recruitment. Unions can make contact with new employees, convince them to stay on the agreement, and gain their membership. The proposed change therefore makes recruitment a whole lot harder for unions.

These three proposed changes will probably not make much difference to the average worker or most employers. The overwhelming bulk of today's workforce is not unionised or covered by a collective agreement.

Employers who are party to collective bargaining will welcome these changes. They will give employers more control over the employment agreement covering their business and workforce.

In the areas of partial unionisation, the changes will make the job of the unions more difficult as it will be harder to secure a collective employment agreement under the amended rules.

Accordingly, it is in the unions' interest to minimise the changes, if they can. It is always much easier to hold on to what you have than to lose it and hope to claw it back under a future Labour government. So watch the rallies and the clarion call. There will be quite a lot of sparks yet to come.