Labor has widened its lead over the government in the latest Newspoll, although Tony Abbott’s better performance has seen an improvement in the Prime Minister’s personal approval numbers.

While Coalition backbenchers can take some comfort from Abbott’s ratings, he starts with very bad figures and in general the poll - which sees Bill Shorten extend his margin as better prime minister - is a good result for Labor.

The ALP has increased its two party lead to 55-45%, compared with 53-47% a fortnight ago.

The Coalition’s primary vote is steady on 38%, with Labor gaining a point to 39%; Greens were steady on 12% and independents and minor parties fell a point to 11%.

Satisfaction with Abbott has risen 3 points to 28%; his dissatisfaction rating is down 5 points to 63%, in the poll published in Tuesday’s Australian.

Former minister Arthur Sinodinos, one of those who backed last month’s unsuccessful spill motion, made it clear on Monday that Abbott remains on notice.

He said backbenchers' mood had been that Abbott should be given time and clear air to change things that were of concern to them and ministers – “and then we see how things go”.

“This is the sort of game where it’s always based on performance,” he told the ABC’s Lateline.

Abbott, having ditched the Medicare co-payment last week, is facing party room pressure over another budget measure, the government’s controversial proposed changes to pension indexation. On Monday he refused to comment on Queensland Liberal backbencher Andrew Laming’s saying some backbenchers had missiles, Exocets and torpedoes pointed at the measure.

In Newspoll Shorten’s satisfaction – which took a fall in the last poll – rose 4 points to 39%, while his dissatisfaction rating dropped 7 points to 42%. His lead over Abbott as better PM widened by 3 points to be 44-33%.

Sinodinos said that party room last month had sent a message that things needed to change. “The Prime Minister heeded the message and changed his behaviour. So we’re all getting behind him to make sure that change works.”

He had supported the spill “because I thought that was the best way to send a message that things had to change in terms of behaviour”.

Sinodinos said there was no succession plan being hatched but, asked about Malcolm Turnbull, he rejected the suggestion that Turnbull was too progressive to lead the Liberals.

He said the Liberal party was made up of a number of strands - a small-l liberal strand, a more conservative strand, and a number of sub-strands. “So it’s a furphy to say X or Y is somehow outside the mainstream of the party. The fact of the matter is, Turnbull is a capitalist. He believes in market principles.” Turnbull was socially progressive on certain issues but so were many others, Sinodinos said.

On the issue of Abbott’s office and his chief of staff Peta Credlin, Sinodinos said the backbench view was that the performance of the office was Abbott’s responsibility.

“We’re in a situation where we’re happy for him to have what arrangement he wants but if something is happening that perhaps other people aren’t happy about in relation to his office he is the one who’s held accountable.”

Meanwhile Abbott on Monday responded aggressively to a report to the United Nations Human Rights Council which attacks Australia over its treatment of asylum seekers.

The Special Rapporteur on torture and other cruel, inhuman or degrading treatment or punishment, Juan E. Méndez said that Australia, by failing to provide adequate detention conditions, end the detention of children, and put a stop to the escalating violence and tension at the Manus centre, “has violated the right of the asylum seekers, including children, to be free from torture or cruel, inhuman or degrading treatment”.

Abbott responded that “Australians are sick of being lectured to by the United Nations, particularly given that we have stopped the boats, and by stopping the boats we have ended the deaths at sea.

“I think the UN’s representatives would have a lot more credibility if they were to give some credit to the Australian Government for what we’ve been able to achieve in this area.”

He also defended conditions on Manus Island as “reasonable under all the circumstances. All of the basic needs of the people on Manus Island are being met”.

Michelle Grattan does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.