The secrecy surrounding Barack Obama's visit is down to safety.

The former President returns to Auckland today, possibly after a bit more golf this morning following his round in Northland with Sir John Key yesterday.

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But most details of his trip to New Zealand have been shrouded in mystery.

That includes a ban on media reporting anything inside tonight's invitation-only dinner function.

Former US ambassador David Huebner told Kate Hawkesby even in a safe environment, presidents and former presidents are targets.

"I think people just want to take care of him. I don't think it's cloak and dagger, I think its just keep that man safe while he's enjoying himself." 

LISTEN TO THE FULL INTERVIEW WITH KATE HAWKESBY ABOVE