Israeli Foreign Minister Avigdor Lieberman threatened Tuesday to seek a court order forcing ministry staff, who have been on strike since Sunday, back to work.
Lieberman, who has been locked out of his own office at the ministry, told a news conference in parliament he was examining "the possibility" of obtaining back-to-work orders.
He also said he was pressing retired judge Steve Adler, the official arbitrator in the dispute, to get union representatives and treasury officials back to the negotiating table.
On Sunday, foreign ministry employees intensified a long-running dispute over pay and conditions declaring a full-scale strike at home and at diplomatic missions around the world.
A foreign ministry staffer told AFP talks were to open later on Tuesday, and media said negotiations could last throughout the night.
Lieberman said the lockout at the ministry's Jerusalem headquarters "crossed all boundaries."
"I have ordered ministry management to cut all contacts with the workers' committee until work is resumed," he said.
Israel media said the open-ended walkout was the first by diplomats in the country's 65-year history.
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The latest step ratcheted up industrial action that has been in place since the wage talks on March 4.
Since then, the ministry website said, diplomats have not dealt "with foreign representatives... official visits of any kind, either in Israel or overseas," nor issued visas or provided consular services.
Officials have said the strike could jeopardise a trip by Pope Francis to the Holy Land, set for May.
The Vatican said earlier this month there were no plans to cancel the trip but confirmed the dispute was "likely to cause complications" in preparing for it.
The strike is also casting a shadow over preparations in Nepal for what coordinators say is the world's biggest celebration of the Jewish Passover holiday.
An orthodox Jewish group organises the Passover feast in Kathmandu every year, attracting hundreds of people from around the world, including Israeli tourists.
But the massive celebration, on April 14 this year, relies on the Israeli embassy in Nepal to help import supplies for the feast.
"We have a problem. We have not been able to get any food shipments through so far for this Passover," said Rabbi Chezki Lifshitz, co-director of Chabad House Nepal.
"I hope the strike will end soon, if it ends in the next three to four days, we can still try to organise the celebration like every year," Lifshitz told AFP.