Speculation over the prime minister's leadership grows as his government takes a plunge in the latest opinion poll

Senior government ministers are pledging their support for prime minister as a new poll shows support for the Turnbull government has taken a dive amid speculation of a possible leadership challenge by home affairs minister Peter Dutton.

Source: AAP

The latest Fairfax/Ipsos poll published on Sunday night found the coalition's primary vote has dropped from 39 to 33 in just a month.

Labor also opened up its advantage over the coalition, now leading 55 per cent to 45 per cent on a two-party preferred basis.

Prime minister Malcolm Turnbull's personal approval also took a battering, falling from 57 to 48 per cent.

Bill Shorten's standing as preferred prime minister rose from 30 to 36 per cent.

The plunge comes as the Liberal Party struggles to achieve internal consensus on the National Energy Guarantee, which has fed speculation Mr Dutton may make a move for the Liberal leadership with the support of conservative colleagues.