Two Colourful Orb Web Spiders.

Leucage dromedaria

This is an unusual orb web spider who builds its web horizontally, near the ground.

If seen running, it is a silver streak, very obvious against the foliage, but hard to catch.

It hangs upside down in its web.
From above, the dark tummy is hard to see and birds are less likely to find it.
The bright back is lost against the sky, when seen from below.
Humans need a mirror to check this out, but an insect flying up from the ground blunders into the web.

The horizontal orbweb spider is also found in Australia, and probably reached New Zealand from there.

This one cunningly built the web vertically, in a glass house, beside the window, where the camouflage also works.
Insects do not fly through window glass, but I guess they smash into windows and this spider is kindly going to stop them hurting their noses.
In return, they will be eaten.

Poecilopachys australasiae

This beautiful, jewel-like  spider is found in gardens, often on citrus trees (in this case a mandarin).

It arrived in Auckland, New Zealand from Australia in the 1970's and is now spreading over the rest of the country.

The two-spined spider builds an orb web at night, but eats it by sun-rise.
It sits quietly through the day, not always under a leaf.
This seems dangerous, as birds can probably see this glowing beauty as easily as humans can.

However, it is called a "bird dropping spider" and birds presumably avoid it for fear of pecking at a mistake.