New Zealanders are being asked to join the challenge to raise funds to help families with sick children

On average, families travel more than 210-kilometres from their home to a Ronald McDonald House to be close to their hospitalised children.

Over 800 people are expected to join the charity's House to House challenge this month - getting sponsored to run, walk, bike or swim a distance of their choosing.

Chief executive Lisa Tai says they're almost at full capacity in Auckland.

She says it challenges like this that ensure they don't have to turn anyone away.