His collection is now valued at more than $70,000 and is to be a feature of an Auckland stamp auction today.
"The advertising was used only for a year by New Zealand Post, because people licked the back of the stamps and there was concern that the ink would be harmful," said David Holmes, of Auckland City Stamps.
"But it was a world first for New Zealand in putting ads on the back of stamps sold over the counter and the fantastic collection has drawn interest from New Zealand and overseas."
Mr Holmes said Mr Petit specialised in the issue and was a prominent stamp dealer from 1965 to 1975.
The collection was last seen in public in 1967 at the National Exhibition in the Whakatane Memorial Hall which had a 24-hour guard over the $500,000 of rare stamps on display.
It was a time when Post Office technicians were flat out converting stamp vending machines to take decimal coins instead of pennies, threepences, sixpences and shillings.
"We have never seen a collection so concentrated and a complete reconstruction of 240 stamps done in panes of 60 in their settings," said Mr Holmes.
"In 1893, the most common stamp to post a letter cost a penny or tuppence but there were different values up to a shilling and the higher the value the harder it is to reconstruct all these stamps.
"Most of the colours are like red or mauve or red-brown but the harder colours to get are the blues and greens.
"There are fewer around - in fact, they are very rare - and they are more expensive.
"It would have taken thousands of stamps to put these reconstructions together and the quality of each stamp is very good."
Mr Holmes said Mr Petit's collection passed on to his family, who recently sought advice on selling them for the first time.
Mr Holmes said the $70,000 value of all the lots making up the collection was a conservative estimate.
About 7400 advertisement stamps in 34 lots are offered in the auction.
