There are options if you worry you might miss a home loan payment.

New Zealand homeowners with loans worth more than $3 billion have fallen behind on their mortgage payments.

The banks report the amount of home lending that is "past due" and impaired in their regular disclosure statements.

The big four banks had a total of $3.1 billion in past-due loans on their books in their most recent statements. These are loans that have not yet been classed as "impaired assets" by the banks - they still think they can expect to see repayments eventually.

PEtER MEECHAM/FAIRFAX NZ A mortgagee sale isn't usually the best option for the bank, and chances are they'll work with you to avoid one.

Most of the overdue loans' payments were only up to a month late but $257 million in loans had repayments more than three months overdue.

In addition to that number, they have collectively given up on getting repayments out of loans worth about half a billion dollars.

READ MORE:

* NZ banks turn down customers over 'minor' credit problems

* Personal finance: Nightmare of mortgagee sales

BAGRAPHIX/123RF It's best to get in touch with your bank as soon as you can if you risk falling behind on your mortgage.

While the numbers seem big, the amount of mortgages going sour has improved over recent years.

Banks wrote off $22m in loans in the three months to September 2015, compared to $7 million in the three months to June this year.

They are also a tiny fraction of the total mortgage market: There is almost $225b in active home loans at the moment.

Westpac said the volume of loans with repayments more than 30 days overdue was less than half what it was five years ago.

An ASB spokeswoman agreed the trend was for fewer troubled mortgages.

"Mortgage arrears across the industry have been improving over the last few years as customers take advantage of strong economic conditions and low interest rates to pay down their debt."

Mortgage arrears are tied most closely to the fortunes of the labour market – while unemployment is low, people do not usually have so much trouble paying their loans.

While a strong housing market helps those find they need to bail out and sell a property, it does not have an effect on arrears rates.

Banking expert Claire Matthews said if there was another recession it would be likely that arrears rates would increase. More people could also start to struggle if interest rates increase significantly without income rises to match.

She said how long a bank would allow a customer to remain behind on their loan before they took action to sell the house would depend on the individual's circumstances.

"If it's the first time they've gone into arrears they might not be too worried but if you're a regular they will be a lot tougher. Also if they are concerned about their security or have additional information that the reason you're in arrears is something serious as opposed to a minor hiccup they will act more quickly."

Matthews said banks' technology enabled them to monitor customers' accounts and flag any that looked like they might be getting into trouble.

"If you're suddenly overdrawn on your account before every pay or you're constantly drawing your credit card up to its limit, those would be signals that they could see that would mean the situation needs to be monitored."

She said people who were getting into trouble often tried to hide the problem and refused to talk to their banks about it.

But the best thing to do was to take action early.

"They seem to think if they don't look at it, everything will go away and they don't talk to their creditors. People say banks are horrible and all they want to do is sell you up but they don't. Banks want to get repaid and it's better if they can get you to repay the loan and pay interest."

She said banks would usually want to work to get their borrowers back on track. A mortgagee sale was often not the best outcome for the bank because it was a lot of hassle and they could not be guaranteed they would get all their money back.

Broker Glen McLeod said there should be fewer borrowers getting into trouble because new Responsible Lending Code obligations had made banks extra cautious.

"There is usually enough there to cover. But that being said, life does happen as well."

He said people should try to get help before they got into arrears, because there were fewer options once they had fallen behind on repayments.

"The banks would prefer to know before a problem happens, they they can work with with you."

Sometimes people who were already in arrears could be moved to a non-bank lender for 12 months, who would allow them to stop making payments and instead add the interest bill to the amount owed, McLeod said. He said that was only an option for people with enough equity and should be done with a mortgage adviser's help.

"That gives them time to get a new job or sell the property if they have to. The worst thing you can do is put your head in the sand."

Karen Scott-Howman, chief executive of the New Zealand Bankers Association, agreed: "The earlier you talk to your bank, the more likely it is they can help. Banks can talk to you about budgeting and provide advice to help you to get back on track. In more serious cases, it may be possible for your bank to extend the term of your loan, adjust repayment amounts or provide a mortgage repayment holiday."

What to do if you're in trouble