Diplomats at the United Nations on Tuesday were harshly critical of Israel's ongoing failure to appoint a permanent ambassador to the UN, saying it has essentially forfeited the arena to the Palestinians.

While Israel is represented by an acting ambassador, Meron Reuben, he lacks the authority of a permanent representative.

But Prime Minister Benjamin Netanyahu and Foreign Minister Avigdor Lieberman were unable to agree on a permanent candidate for months, and the man they finally settled on, Environmental Protection Minister Gilad Erdan, rejected the job this week.

Diplomats described this as "gross irresponsibility" on Netanyahu's part.

"A prime minister who was a UN ambassador ought to know how important the UN is to Israel, especially at the height of an assault on its legitimacy," said one former senior Western ambassador. Netanyahu was Israel's ambassador to the UN in 1984-88.

The Palestinians are promoting several UN initiatives opposed by Israel, including a Security Council resolution condemning the settlements and demanding an immediate halt to settlement construction. They are also mobilizing a General Assembly majority to back a unilateral declaration of statehood in September.

And even if Israel succeeds in preventing a vote on the settlement resolution, the prevailing view is that the Security Council will issue a statement condemning Israel's settlement policy.

The combination of the lack of Israeli-Palestinian talks and Jerusalem's rocky relationship with the White House have brought Israel's standing at the UN to an almost unprecedented low, diplomats said - which may be why Erdan didn't want the job. Nor would his appointment have done much to change this, they admitted.

"But at least Erdan would have been accepted at the UN as someone who represents the prime minister, and his voice would have been heard loud and clear," one senior UN diplomat said. "Whereas the present ambassador is seen as an appointee of Foreign Minister [Avigdor] Lieberman - whose reputation at the UN is dubious in the extreme - and as a temporary appointee unacceptable to the prime minister. That image severely undermines his status and significantly restricts his ability to have an influence."

Another diplomat bluntly described Reuben as a "featherweight." Reuben vehemently rejected these assertions, insisting that his lack of official credentials hasn't impaired his functioning.