The Prime Minister succumbed to a week of ferocious opposition pressure on Friday, sacking his besieged Human Services minister, Stuart Robert, for breaching ministerial rules relating to conflict of interest. Before the fall: Prime Minister Malcolm Turnbull is all smiles the day before the sacking of Stuart Robert. Credit:Alex Ellinghausen He was found to have behaved in a way that was "inconsistent" with the ministerial standards - or code of conduct - by accompanying his friend Paul Marks, a millionaire businessman and Liberal Party donor, to a contract signing ceremony and related functions in China in 2014. In the course of an investigation ordered by Mr Turnbull, Mr Robert revealed he had become aware that shares in Metallum Holdings, a company in which Mr Marks was also a shareholder, had been allocated to his trustee before the visit. Mr Robert recognised that this connection would create the impression that at the time he went to Beijing he had something personally to gain from the Nimrod Resources project, Mr Turnbull said in a statement.

"As a result, Mr Robert has asked me not to consider him in the pending reshuffle of the ministry," Mr Turnbull said in a short statement. Stuart Robert says he wanted to ensure there was no perception of a conflict of interest. Credit:Alex Ellinghausen His departure, which follows the Christmas resignation of Cities Minister Jamie Briggs and the standing down of Special Minister of State Mal Brough, has added to an atmosphere of disintegration. This week also saw the resignations of longstanding stalwarts of the Coalition frontbench, Warren Truss and Andrew Robb. Mr Truss was replaced on Thursday evening as Nationals leader and therefore Deputy Prime Minister by his own former Nationals deputy, Barnaby Joyce. Peta Credlin has words with Stuart Robert in 2013.

His elevation, regarded as a potential risk factor for Mr Turnbull after the dull but steady management of Mr Truss, immediately saw an embarrassing contradiction when Mr Joyce fronted morning television to declare that Mr Robert had done nothing wrong. That was despite a sub-committee of cabinet determining - the previous night - that the minister had to go. In a further sign of disarray, it was Mr Joyce who later publicly confirmed Mr Robert's removal declaring that the evidence had pointed to his sacking, which he described as "goodnight Irene". Flush with success after its week-long pursuit of Mr Robert, Labor leader Bill Shorten dared Mr Turnbull to join with Labor to support campaign finance reform, including much greater transparency for donations. Mr Turnbull has begun the difficult task of designing the frontbench team he will take to the election whether early or at the expected time of August to November.

Among those tipped for promotion are Queensland Minister for International Development, Steven Ciobo, who is set for Mr Robb's former cabinet-level post of Trade, as well as Victoria backbencher Dan Tehan. Mr Turnbull will also need to find a cabinet post for the new Nationals deputy leader, Fiona Nash - currently in the outer ministry in Rural Health. The pressure to manage all of the competing demands will see the Cabinet expanded from 21 to 22 with the Nationals to get the extra spot. However, because of the requirement to manage regional balances, the new Nationals appointee will also need to hail from Queensland - thanks to the loss of Mr Truss. That means a choice between the little-known Keith Pitt and rookie senator Matt Canavan. Mr Turnbull may also look to elevate others to the outer ministry, including the strongly performing Assistant Minister for Multicultural Affairs, Concetta Fierravanti-Wells from the party's NSW right faction. Mr Robert's fate was sealed after it was reported on Monday that he had attended a mining deal between Nimrod Resources - run by Mr Marks - and the Chinese government-owned company Minmetals.

Despite saying he was in China in a "personal capacity", Mr Robert also took Nimrod executives into a meeting with a Chinese government minister. Any decision to go to an early election would need to weigh up whether the Electoral Commission could make the necessary changes to conduct the election under new voting rules in time. An early election would also put the two houses of Parliament out of sync, causing half of the senators' terms to be backdated to July 2015 and necessitating another half-Senate poll within two years. Follow us on Twitter