Muldoon, Lange or Key? Who are New Zealand's best Prime Ministers?

A man who claims to have been on first name basis with all New Zealand prime ministers since 1957 has written a book about them, and those who came before.

Historian and former cabinet minister Dr Michael Bassett launched his book on Wednesday called New Zealand' Prime Ministers - From Dick Seddon to John Key.

Dr Bassett rates Peter Fraser, Richard Seddon, William Massey, Helen Clark, David Lange and John Key as our top six prime ministers.

As for prime minister's in the modern, Dr Bassett has some advise.

"They've got to be highly intelligent, high energy, a restlessness to solve new and old problems," he says.

"Above all good health and comfortable in your own skin - John Key style, you're a winner."

Dr Michael Bassett has recently released a book about our country’s leaders. Source: Q+A