I found this plant!
Coast Daisy-bush
Olearia axillaris

This rapid-growing, dense, erect, medium-sized, greyish-leaved shrub is not so much a species of coastal cliff tops where soils are heavy, but a plant of coastal sand dunes like those at Point Impossible or the north end of Jan Juc where beach sand settles in deep layers. It is an important primary coloniser of beach sand and highly tolerant of coastal salt winds. It can often form dense stands, particularly on newer dunes.

Leaves are narrow and linear; the underside white and cottony. The upper surface is bluish-green providing an overall greyish quality to the plant.
Flowers are white and produced en masse on new growth in the axils of leaves during summer. Windblown, fluffy seedheads follow in autumn.

Whilst this plant can be grown in heavier soils it appears to be much shorter-lived under those conditions.

Plant form
Shrub
Flowering season
Summer, Autumn
Flower colour
White
Leaf colour
Silver Gray
The two sides of the leaf are different colours
Leaf shape
Linear
Leaf edge
Entire
Required Sunlight
Full Sun
Other Features
Drought tolerant, Erosion control, Fragrant, Insect pollinated