New Liberal Party president Nick Greiner has urged Malcolm Turnbull and Tony Abbott to "be adults" and resolve their long-standing feud, warning the public displays of disunity will cost the Coalition the next election.

Blaming the simmering tensions for the party's consistently poor polling, Mr Greiner said he would be meeting with Mr Abbott in coming weeks to encourage him to sit down with Mr Turnbull and settle their differences.

"They need to resolve it face-to-face and they need to resolve it directly, not through intermediaries," he told Sky News.

"If it isn't resolved, if we are not able to present a compelling, unified face to the Australian public, we won't win the election in two years' time."

Mr Greiner said everyone needed to be adults about the situation, even though he could understand why Mr Abbott has "responded in a particular way" to being toppled as leader in 2015.

At the time, the former prime minister promised there would be "no wrecking, no undermining and no sniping" but Mr Abbott has consistently waded back into the political fray to defend his legacy, criticise the Government's performance or push a conservative agenda.

In recent weeks, he has inflamed tensions even further by giving a series of speeches and interviews, outlining an alternative policy vision to "make Australia work again".

Mr Turnbull has been pushing back against the criticism and used Mr Abbott's words against him when he declared that the Liberal Party should occupy the "sensible centre" of politics.

The constant navel-gazing has frustrated Nationals leader Barnaby Joyce, who warned the Liberal Party was becoming a "philosopher's club" and would drive voters to parties like One Nation.

But Foreign Minister Julie Bishop hit back at Mr Joyce's remarks, saying she could not understand why people "from our own side would criticise the Government's performance".

"Because all it is doing is driving people to Bill Shorten, in fact," she told Insiders.

That view is shared by Mr Greiner, who said the Liberal Party needed "to stop talking about ourselves" because Labor and the Opposition Leader were "totally escaping scrutiny".