Heather du Plessis-Allan: Winston Peters' spending is denting the coalition's credibility

Prime Minister Jacinda Ardern, Deputy PM Winston Peters, Regional Development Minister Shane Jones and Economic Development Minister David Parker at the launch of the Provincial Growth Fund in Gisborne.

Bringing in Winston Peters as a coalition partner clearly hasn't come cheap.

When he screwed that coalition deal out of Labour, he screwed hard. We're starting to see that now. The more we hear, the more eye-watering the dowry for his hand marriage becomes.

The $1-billion-a-year regional slush fund is already offensive enough in its profligacy. It'll be interesting to watch Shane Jones find enough projects to spend that amount of money on.

Personal highlights include a church restoration in Taranaki, a roundabout near Jones' house in Northland and a whoopsy spend on a project connected to a man referred to the Serious Fraud Office. And we're only six months in.

Now we've learned of Peters' own portfolio spend-up: nearly $1b for diplomats and foreign aid.

Commentators and politicians often like to explain the more boring aspects of government finances using the analogy of a family. You know, comparing national debt to a family mortgage, tax revenue to a wage, social spending to buying groceries.

If that's the analogy, then Peters is the wife who just blew a week's income on luxuries to impress her new friends.

And that's all this is. Putting on a good show in front of Peters' new friends.

He said other countries look at our "bank account" and what we "have spent or not spent" and he was finding our budget "too embarrassing". So he's throwing some cash at a flash new embassy in Sweden and freebies for the Pacific.

What's that if not keeping up with the Joneses?

All of that largesse would be fine, if it wasn't that the family is already scrimping to send the kids to the doctor.

This is where it becomes Labour's problem. Peters has just earmarked huge amounts of money for people who don't live in this country, while his coalition partner is apologising for running out of money for us.

Being broke has forced Labour to break two election promises and wind one back.

First, there's the broken promise to cut doctors fees by $10 for low-income earners. Labour says there isn't the cash, so that will have to wait for next year.

Far more quietly, Labour has also delayed the promise of giving pensioners extra money to help heat their homes this winter.

Labour promised to pay the extra money into pensioners' accounts from May to September. There's no money yet. It won't arrive till July 1. That's seven weeks from now and it's already cold.

Then, Labour has broken the promise of no extra taxes by increasing fuel excise and adding GST to offshore online purchases. It looks like Labour's scratching around trying to find whatever extra revenue it can, just to make ends meet.

Letting Peters act like the Kim Kardashian of foreign affairs is expensive. He's putting a dent in the credit card and the Coalition Government's credibility.

Early on in this government, it was often predicted that the three-headed coalition would tear itself apart in a blaze of tempers and egos. In reality, it looks more likely to be slowly eroded by thinly stretched budgets, bad spending and excuses.

It's all about priorities. That's what Labour said when it delayed the cheaper doctors' visits. Priorities, priorities, priorities. When there isn't enough cash around, you have to prioritise some spending over others.

Well, how can you prioritise a new embassy in Sweden over doctors' visits for poor kids? You can't.

Sure, governments can and do spend on both at the same time. It's just a little unfortunate that the cost of Peters' foreign affairs extravagance is almost exactly the same as the doctors' visits would have cost.

Already Peters' dowry is expensive. It could become even more so as we discover further details of his wily coalition deal. If that's the case he could cost Labour more than just money.