KING tides will begin their twice-yearly lap of the NSW coast this morning, and residents are being asked to get out their cameras.

The tides will begin in Eden at about 8.30am, reach Sydney at 9.33am and hit Newcastle by 9.39am.

Environmental organisation Green Cross hopes to use the event to draw attention to rising sea levels.

Green Cross chief executive Mara Bun is asking coastal residents to photograph their local king tide and upload the pics to help create a digital picture of future sea levels.