Crown Prince Fumihito said Friday he does not know whether the marriage between his daughter Princess Mako and her fiance Kei Komuro will take place, with the plan still pending following reports that Komuro's family is involved in a financial dispute.

"I have not heard from my daughter about it, so I do not know how things are at this stage and what she thinks about it," said the 53-year-old prince, who became heir to the throne with the enthronement of his brother Emperor Naruhito on May 1.

The imperial succession took place following the abdication of their father, former Emperor Akihito, on April 30.

He made the remarks in a press conference with his wife Crown Princess Kiko ahead of their first official visit to Poland and Finland from Thursday to mark the 100th anniversary of the two countries' establishment of diplomatic ties with Japan.

Princess Mako and Komuro, both 27, announced their engagement in September 2017 and said their wedding would take place in November 2018, but the Imperial Household Agency said in February last year that the couple will delay the event until 2020.

The decision followed a string of reports that Komuro's mother was involved in a money dispute with her former fiance, including over educational expenses for her son that the former fiance shouldered.

Komuro said in January his family believes the financial issues have already been resolved, but his mother's former fiance was reportedly unconvinced.

The princess' boyfriend from university days has been studying at Fordham University's law school in New York since August last year, aiming to pass the state's bar examination.

(Kei Komuro (L) and Princess Mako)

In November, the prince asked Komuro's family to resolve outstanding financial issues if they want the wedding to go ahead. "If (their marriage) cannot be celebrated by many people, we cannot hold the betrothal ceremony," he said.

The crown prince and his wife will stay in Poland through July 2 and travel to Finland before returning on July 6. They are scheduled to meet with the presidents of both countries and attend various commemorative events.

"I look forward to deepening exchanges with the people of the countries I am visiting," the crown prince said.