Labor has accused Malcolm Turnbull of standing by incompetent ministers to save his own job.  A week of parliament came to a messy end with the government - for the first time since Federation - supporting a motion condemning itself.  Revenue Minister Kelly O'Dwyer copped most of the blame as she was in charge of government business at the time.  The federal opposition said the embarrassing vote loss on Wednesday night - plus a previous lost vote because Justice Minister Michael Keenan left parliament early, a $100 million error in a draft tax law and the Senate running out of bills to debate - underlined the chaos in the government.  Labor leader Bill Shorten told parliament the only reason Mr Turnbull was keeping the ministers behind the bungles in their roles was he was afraid of losing his own job.  "What exactly does a minister have to do to get the sack in your government?" he asked.  Mr Turnbull said the opposition was playing political games and not interested in issues that matter.  "The ministry is governing. The ministry is delivering. The government is securing legislation through the parliament," he said.  The prime minister said in the past week the government had updated the Singapore-Australia free trade agreement, protected emergency services volunteers through changes to Fair Work laws and cut taxes for middle-income earners.  "What does the leader of the opposition have to savour? Some games in the house, a pious amendment, his little win. Well, we won't begrudge him his small pleasures but we will get on with the job of governing for all Australians."  Opposition business manager Tony Burke said it was not about obscure parliamentary rules.  "What lies at the heart of this is you have government ministers that pay no attention to the votes in the parliament ... when laws are being made," he said.  The slanging match came as Nationals MP George Christensen warned the coalition agreement could be broken if Mr Turnbull went ahead with an alternative to the same-sex marriage plebiscite promised at the election.  Nationals leader Barnaby Joyce told reporters in Canberra there was no danger of it, as the government was committed to the plebiscite as the only way to deal with the issue.  ""Our Plan B is balance the books, build the dams, get inland rail going ... keep our agricultural exports going - that is the plan," he said.  The plebiscite bill was debated in the lower house but has yet to pass.  Labor and the Greens have pledged to block it in the Senate.  Parliament resumes on Monday with the Senate holding estimates hearings.
The prime minister says Labor is playing political games by talking up the significance a series of missteps in parliament.