Israel and New Zealand have restored full diplomatic relations after Tel Aviv formally apologized for two alleged spies who tried to illegally obtain a New Zealand passport, Prime Minister Helen Clark said Sunday. Ties between the countries plunged last year following the incident, which led to the conviction and imprisonment of two men New Zealand alleges are Israeli agents. Uriel Zoshe Kelman, 31, and Eli Cara, 50, were sentenced to six months in prison after pleading guilty to the passport charge, but were released and deported after serving about two months. Clark said last year that she had "no doubt whatsoever" the two were Israeli spies. "The New Zealand government has strong grounds for believing that the two men convicted were working on behalf of an Israeli intelligence agency," Clark reiterated in a statement Sunday. New Zealand demanded a public apology from Israel and a commitment to prevent another such breach of New Zealand laws by its officials in the future. Clark also imposed a range of diplomatic sanctions on Israel from July 2004, including halting the approval of a new Israeli ambassador. In a letter released Sunday, Israeli Foreign Minister Silvan Shalom said Israel wished "to express our regret for the activities which resulted in the arrest and conviction of two Israeli citizens in New Zealand on criminal charges and apologize for the involvement of Israeli citizens in such activities." "Israel commits itself to taking steps to prevent a recurrence of similar incidents in the future," he wrote to counterpart Phil Goff. In response, Goff said the issue is now "behind us" and the two states "should ... resume friendly diplomatic relations." Clark said that "restrictions on official contact with Israel are being lifted today (Sunday). The new Israeli ambassador can now be accredited, and visits and other diplomatic activities can be restored." She added that official inquiries had revealed that "a very small number" of New Zealand passports had been obtained by those working on behalf of Israeli intelligence. "Those passports have been canceled and that it would be futile for attempts to be made to use them," she noted. Since the Israeli passport fraud was uncovered, New Zealand passports have been made more secure through the inclusion of biometric data on the holder, stricter checking procedures and the reduction from 10 years to five in the time a passport remains valid, according to a report of The Associated Press.