When the Government came to power, the prevailing wisdom was Labour would, as usual after a defeat, implode into warring factions and its leadership would be in disarray. With the opposition MPs busy scrapping among themselves, it was thought National could easily push ahead with its own agenda.

This, of course, failed to happen. Labour is a unified, solid and effective Opposition. In the House it continues to ankle-tap National and in the broader political arena it is succeeding in denting the Government's credibility.

Perhaps Helen Clark's greatest legacy was her smoothly managed departure, first from the leadership, then from Parliament. It gave Phil Goff the chance to work himself into the role and he is now proving to be a match for John Key.

Labour's long stint in power means it has a large group of senior MPs who are more experienced in Government than most of the ministers they face. They have managed to exploit that advantage well during the past few months.

National lacks a "Mallard", a street-fighter, a naughty kneecapper, who can get down and dirty when the times demand it. Gerry Brownlee would be a natural but he is tied up trying to be statesman-like as Leader of the House, and the rest of the National caucus seem far too nice to take on that dirty job.

Labour is strategically targeting Government ministers, applying the pressure on those they think weakest. Having succeeded in taking out Richard Worth, or rather letting Worth take himself out, Labour has now turned its sights on the leopard skin Westie, Paula Bennett.

She revels in a scrap but her tendency to fire from the lip without thinking will land her in trouble sooner or later, they reason. There are also doubts about her ability to comprehend the masses of information a minister must absorb. Bennett, reportedly, is not fond of reading and prefers to have issues explained to her on whiteboards - an allegation she denies. Sadly for her, government is about long reports and lengthy policy analysis. All Labour can do is keep chipping away at the Government's credibility, like water dripping on a stone, until the public becomes convinced National has lost its way or lacks the competence to command the Treasury benches. So far, Labour has done a good job of beginning that process of erosion.

The Government, however, is trying to ignore these distractions, which it thinks are irrelevant. That could be a fatal mistake.

A week ago in Christchurch John Key is reported to have told a public meeting National would win the next election by concentrating on the things that count. Delivering a strong economy, keeping communities safe, having a health system that works and keeping the country headed in "the right direction".