Prime Minister John Key has canned his schedule today due to what the Herald understands is a serious family illness.

Mr Key was to have spoken at a tourism industry event in Wellington this morning but pulled out not long before he was due to speak.

The Herald understands he withdrew due to the serious illness of a family member, although it is also understood that wife Bronagh and children Stephanie and Max are fine.

Mr Key is expected to resume his planned schedule tomorrow.