A panel of experts studying the issue of allowing female members of Japan's imperial family to retain their status after marrying commoners is considering not granting such status to their husbands and children, government sources said Friday.

The possibility has been raised as controversy over the planned marriage between Princess Mako, a niece of Emperor Naruhito, and commoner Kei Komuro, continues to simmer. Some members of the panel have indicated their opposition to granting imperial status to Komuro, who recently graduated from a law school in New York.

File photo shows Princess Mako (R) and Kei Komuro attending a press conference in Tokyo on Sept. 3, 2017. (Kyodo)

The marriage of the couple, both 29, has been postponed for more than two years following media reports of a financial dispute between Komuro's mother and her former fiance, who claims she owes him over 4 million yen ($36,000) including money that covered Komuro's educational expenses.

The advisory panel on imperial succession, chaired by former Keio University President Atsushi Seike, has been discussing whether to allow female members to remain in the royal family after marriage by establishing their own imperial branches.

Under the current rule, female members have to leave the family if they marry a commoner.

According to minutes of the panel's meeting on July 9, all six members agreed in principle that imperial status should not be granted to the spouses and children of female imperial members for the time being.

"In terms of public sentiment, there are high hurdles (to implement it)," one of the members said, apparently referring to the issue related to Komuro.

The imperial family has been contracting under the 1947 Imperial House Law, which limits heirs to a male who has an emperor on his father's side. Emperor Naruhito and Empress Masako's only child is a daughter, Princess Aiko, 19.

Three heirs are currently in line to succeed the 61-year-old emperor -- his brother Crown Prince Fumihito, 55, nephew Prince Hisahito, 14, and uncle Prince Hitachi, 85.

The panel said in an interim report last month that its members agreed on maintaining the current order of succession.

It also said the results of the debate will be organized into two key points -- changing the current rule that forces female members who marry commoners to abandon their imperial status and enabling the adoption of male heirs from former branches of the imperial family.

Based on the panel's discussion, the government is expected to present its conclusion to parliament by this fall.