DM
1n 1996 you would have been paying about 11% interest (Source RBNZ) on your mortgage so your weekly interest bill on a $128k mortgage was $271

According to the 1996 census the average weekly rent in Papakura was $183.48

(if we use your technique you would need to put in $95,000 in cash to keep your mortgage to $67,000 of which the $183 rent would pay the interest plus rates and R&M)

Continuing with the $34k deposit, you are loosing $88 cash a week which you have to fund. Over a year this is $4,576. You will also have to fund say $1,000 in rates plus, say $300 in insurance. So you are having to find $5,876 a year.

What’s repairs and maintenance and capital improvements worth – say $1,000 a year? So all up lets say you are putting in $7,000 a year or $70,000 over the 10 years. Your $185k now gets reduced to $115,000 + plus your initial $34k = $149k all up.

Alternatively you could have out your $34k into the bank and cleared $50,000 (4% net compounding) after 10 years. Add to this the $70 you could have saved by not spending it on the rental you would end up with $120k.

So the easy low risk route clears you $120k and the other way gives you $149k –assuming the property is rented out 100% of the year.