"I agreed with my counterpart Plenković to meet on the 27th in Zagreb, where we will continue the discussion on the border between Slovenia and Croatia. I will of course advocate the position that this must be the central topic of the talks and I wish to discuss implementation [of the arbitration tribunal's award]."

"This will be a continuation of dialogue and I hope we move in the direction we are advocating. Let's let time run its course and see where the debate will take us," Cerar told Slovenian reporters in New York.

The date of the meeting was also confirmed by the office of Prime Minister Plenković, who reiterated his long-standing position in New York that the border issue needs to be resolved in bilateral talks after Croatia walked away from arbitration.

Cerar has previously insisted he would only meet Plenković if the implementation of the arbitration tribunal's award is on the agenda.

The position of Foreign Minister Karl Erjavec has been slightly different, as he asserted that Cerar should only travel to Zagreb once the Croatian government accepts the tribunal's award.

President Borut Pahor has said that resolving the issue in bilateral talks was unacceptable. "Even conceding to a willingness to talk about implementation with a new bilateral agreement would mean the legal validity of the award would be significantly weakened," he told the STA.

Nevertheless, he said Cerar should visit Zagreb, "not because Slovenia would show weakness but because it would show strength."

Cerar also plans to discuss arbitration with world leaders he will meet on the margins of the UN General Assembly, and he highlighted the importance of US President Donald Trump's speech at the UN yesterday.

He noted that Trump had highlighted the need to respect the rule of law when he talked about the South China Sea, where borders were subject to arbitration. "This is very important for our case," he said.

Trump in his speech said: "We must uphold respect for law, respect for borders, and respect for culture, and the peaceful engagement these allow."

In July last year an arbitration tribunal rejected China's demands and ruled in favour of the Philippines, but the Chinese authorities rejected the ruling as void.

The US has advocated the position that arbitration was an issue for Slovenia and Croatia to resolve, which Slovenia has interpreted as support for its position.