Two Tongan princesses have left the royal family in "disarray"after snubbing tradition and opting to marry commoners.
Princesses Salote Lupepau'u Tuita, sixth in line to the throne, is marrying a former rugby player, while her younger sister, Princess Frederica Tuita, who is tenth in line, is marrying the son of a businessman.
King Tupou VI could annul both marriages under the constitution, but he is not expected to do so. However, previous rulers have cancelled such marriages and insisted that members of the royal family agree to hastily arranged marriages.
Princess Frederica reportedly delivered an additional affront after deciding to wed her partner, Johnny Filipe, in an Anglican church in New Zealand this weekend, rather than a Free Wesleyan church, which is headed by the King.
She wrote in a blog last year that members of the royal family should marry for love and the tradition of marrying fellow nobles encouraged "social climbing".
"The ancient idea of marrying to raise one's status or replenish one's blue-blood has reached its peak and end," she wrote.
Princess Salote is due to marry a former Tongan rugby national, Epeli Taione, in Fiji on August 17, according to Kaniva Pacific, a news website.
"Both weddings have caused surprise within Tongan circles considering the protocol and how they bypassed strict rules that control royal families and who they can marry," the website said.
"Traditionally, it was not normal for a high ranking royal woman to marry a commoner or a much lower ranking chief."
A Tongan political scientist, Dr Malakai Koloamatangi, from the University of Canterbury in New Zealand, said the practice of royals marrying each other was designed to "keep the blood undiluted as much as possible".
He said previous monarchs had cancelled marriages to commoners but such annulments were unlikely for royals who were not high in the line of succession.
"The one that is tenth in the line probably has less in line than the one who is number six," he told ABC News.
"Things have changed more and more these family members are getting away with things. More and more the wider family is marrying commoners. The pool is becoming very small."
A lavish wedding last year between the Crown Prince and his second cousin proved controversial, and prompted concerns about potential genetic risks to their children.