Cabinet members who oppose a strike on Iran said on Wednesday Kadima head Shaul Mofaz might backtrack and align with the more hawkish Benjamin Netanyahu, now that the two are in the same government.

Mofaz, who has consistently opposed an Israeli attack on Iran's nuclear facilities, joined the Netanyahu government on Tuesday despite having called the prime minister a liar. After taking over as Kadima head this spring, he repeatedly pledged to lead the opposition.

"How can one know for sure that he won't be equally fickle on Iran?" a cabinet minister said.

Mofaz is to become a member of the forum of senior ministers, alongside Foreign Minister Avigdor Lieberman, Defense Minister Ehud Barak, Interior Minister Eli Yishai, Finance Minister Yuval Steinitz and ministers Moshe Ya'alon, Dan Meridor and Benny Begin.

Mofaz may tilt the balance in the forum, which is divided on how to deal with Iran. Steinitz, Lieberman, Netanyahu and Barak are considered part of the hawkish camp, whereas Ya'alon, Meridor, Yishai and Begin are considered opponents of an Israeli strike they deem a dangerous mistake.

One member of the forum told Haaretz that Mofaz had been inconsistent about key security issues in the past. "He thought the [Gaza] disengagement was a mistake and that we shouldn't pull out without an agreement," the minister said. "But then he saw that [then-Prime Minister] Ariel Sharon was determined, and he aligned himself with him. The same might happen in the case of Iran."

Mofaz's aides dismissed the allegations; one said "few members of the forum can boast Mofaz's years-long security record. They should refrain from lecturing a former IDF chief of staff and defense minister."

They said Mofaz had not changed his mind and still believed that a U.S.-led diplomatic campaign was the best way to halt Tehran's nuclear program.

Over the past few weeks, Mofaz has slammed Netanyahu's harsh words about Iran, saying he is "sowing panic." But the daily Maariv, citing sources who took part in the talks between Netanyahu and Mofaz, reported that the two men see eye to eye on measures for thwarting Iran's nuclear program. The sources gave no details.

A minister said the invitation of Mofaz to a meeting with the European Union's foreign policy chief, Catherine Ashton, was an attempt by Barak and Netanyahu to "sweet-talk" Mofaz into their camp by creating the impression he's in on decision-making. The meeting with Ashton was dedicated to the Iran crisis.

Ashton visited Israel ahead of the next round of negotiations between Iran and six world powers - the United States, Russia, China, France, Britain and Germany. The talks are due to take place in Baghdad later this month.

Netanyahu, Mofaz, Barak and Lieberman told Ashton the rhetoric against Iran should be stepped up. According to a senior Israeli diplomat, Netanyahu told Ashton the Iranians have no intention to halt their nuclear program; they are only trying to buy time.