Foreign Minister Stephen Smith announced the expulsion of the unnamed diplomat after an investigation left "no doubt" Israel faked Australian passports used in the assassination of a Hamas leader in Dubai, United Arab Emirates, the Australian Broadcasting Corp. reported Monday.
But deputy opposition Leader Julie Bishop said evidence hasn't been produced that Israel was behind the sham passports.
"In the absence of proof, it would be appropriate to reprimand, appropriate to chastise the Israeli government," Bishop told Sky News.
"There is a widely held view, there is an assumption that the Israeli government was involved, but there is no actual proof."
Bishop said the expulsion was either an overreaction or a decision motivated by politics.
"The government is facing an election. The government is also seeking to pursue a seat on the Security Council," Bishop said. "The government is keen to curry favor within the Arab community."
Several forged Australian passports were used earlier this year in the assassination of Hamas leader Mahmoud al-Mabhouh. Hamas said the assassination was carried out by the Mossad, Israel's foreign intelligence service. The Israeli government has not commented on the allegations.
Smith said investigations by several Australian law enforcement agencies indicated Israel fabricated the passports of four Australians who had Israeli nationality, ABC said.
"The high quality of these counterfeited passports points to involvement of a state intelligence service," Smith said. "These investigations and advice have left the Australian government in no doubt that Israel was responsible for the abuse and counterfeiting of these passports."
Yigal Palmor, a spokesman for the Israeli foreign ministry, called Australia's actions regrettable.
"We regret this step by the Australian government," Palmor said. "It does not reflect the importance and the quality of our relationships."