Australia said Sunday its plans to send asylum seekers for processing in the Pacific appeared untenable due to a court ruling against a similar deal with Malaysia, deepening woes for the prime minister. Immigration Minister Chris Bowen said the government's lawyers had reviewed last week's High Court judgment against the so-called Malaysia solution and advised that it threw the entire offshore processing system into question. In particular, Bowen said the solicitor-general, Stephen Gageler, had expressed "no confidence" in plans to send asylum-seekers arriving by boat to either Papua New Guinea or Nauru, as being contemplated by the government. "The solicitor-general's advice confirms the significant doubts over whether or not the government and immigration minister could make a valid declaration for either Papua New Guinea or Nauru," Bowen said. Canerra's plan to send 800 boatpeople to Malaysia in exchange for 4,000 of the Asian nation's registered refugees was defeated by a majority ruling of Australia's highest court Wednesday in an embarrassing blow for the government. The judges said Australia could not ship asylum seekers offshore unless the country in question -- in ths case Malaysia -- was compelled to adequately protect them. Kuala Lumpur is not a signatory to the UN convention on refugees. Canberra's entire regional processing plan now looks fatally flawed, with Gageler warning that offshore detention on PNG or Nauru was also now not possible under current laws due to similar human rights concerns. The comments will deepen the embarrassment for Prime Minister Julia Gillard, who stumbled at the outset of the regional plan by prematurely announcing that neighbouring East Timor could host Australia's asylum-seekers. She was forced to retreat after strong objections from Dili. Gillard seized power in a party coup last year and failed to win an outright majority at the elections that followed. She has declined steadily in popularity ever since, with the scuttling of her Malaysia deal stoking unrest inside the ruling Labor party about her fragile rule and fueling speculation of yet another coup to replace her. Labor figures are anxious about Gillard's credibility, which many have seen as shaky from the start, with voters wary of the way she came into the top job and her reneging on an election promise not to introduce a pollution tax. Australia's first female leader has reacted defiantly, insisting she was the best person for the job Friday and vowing to stay the course despite public anger about "tough" issues including asylum seekers. Bowen said the High Court ruling threw significant hurdles before offshore processing and warned there was "no clear or easy response" to the sensitive issue of boatpeople, hundreds of whom now hang in legal limbo. "The government (will) now carefully consider all its options," he said. Offshore processing was introduced as a deterrent to people-smuggling by the former conservative government of John Howard in a punitive scheme known as the "Pacific Solution", condemned by human rights groups. PNG's Manus Island and Nauru, both being considered as destinations by the current government, were central to the plan, which saw asylum-seekers including children held behind razor wire, sometimes for several years.