Prince William and his wife, Kate, will choose the name themselves but it's almost certain to be traditional and "safe", probably a name already seen for a monarch, Whitelock said.
Elizabeth is up there among the names being tipped for a girl along with Victoria and Alexandra - one of the Queen's middle names. Charlotte and Catherine are contenders too.
Bookmakers have George as the favourite for a boy but Whitelock thinks James is in with a chance following two English monarchs and six Scottish Kings.
Kate's brother is also called James. Another option is Philip after the Queen's consort.
The historian and writer believes the royal couple are unlikely to pick Charles as it would be strange to have two heirs with the same name.
While the Duke and Duchess of Cambridge are a modern couple Whitelock thinks it's unlikely they'll take inspiration from Kate's parents, Michael and Carole.
But all this speculation only relates to the royal baby's first name - most royals have a number of middle names. Prince Charles and his son, William, both have four names.
Allocating middle names is a somewhat "diplomatic activity", Whitelock says.
"Nods in certain directions acknowledge ties, loyalties and previous admirations. The more the merrier in terms of names."
Fellow royal historian Hugo Vickers believes it's easier to guess what names will be on that extended list.
"I would imagine Philip, Charles and William could well appear for the boys' names somewhere and I'm sure Diana would appear somewhere as a girl's name," Vickers said.
Like Whitelock he's also happy to predict certain names won't make the cut.
Vickers notes a British journalist wrote before Prince William's birth in 1982 that the prospect of a Prince Jim or Princess Tracey was mercifully some years off "and it still is".
"I'm sure he or she will be given a good royal name," the writer said.
The Queen will undoubtedly be informed of the chosen names before their announcement but is unlikely to veto what can and cannot be picked.
Whitelock said the Queen would only intervene if William and Kate came up with something "completely left field" like Beatrice or Eugenie.
The academic suggests Prince Andrew and his then wife Sarah only got away with those because the Princesses weren't in direct line to the throne.
Traditionally, royals are named after an immediate family predecessor or a previously successful king or queen.
Whitelock said John, for example, was very unlikely because King John was an unpopular figure who the barons rebelled against.
"That name has quite negative associations."
If the baby is a boy, he will be styled a prince and, thanks to a new Letters Patent issued by the Queen, if the baby is a girl, a princess.
When William was born he was Prince William of Wales and his children will use Cambridge in the same way, becoming HRH Prince (forename) of Cambridge or HRH Princess (forename) of Cambridge.
According to the monarchy's official website: "For the most part, members of the Royal Family who are entitled to the style and dignity of HRH Prince or Princess do not need a surname.
"But if at any time any of them do need a surname (such as upon marriage), that surname is Mountbatten-Windsor."
- AAP
