Labor has extended its lead over the Coalition in the latest Newspoll, with the government struggling to catch up since its unpopular federal budget.

Labor’s primary vote is up two points to a three-month high of 36%, compared with the Coalition’s 38%.

In two-party-preferred terms Labor leads by 54%-46%, indicating a crushing victory if an election were held today. The government’s ratings have fallen one point since the last poll was conducted a fortnight ago, with Labor’s standing up one point.

The Coalition has been behind in the polls since April. Its ratings plummeted after the budget, and Labor’s lead in 13 consecutive polls since is its longest run since 2010, when Kevin Rudd was prime minister.

The poll results were flipped this time last year, with the Coalition leading the two-party preferred vote 56%-44%.

Tony Abbott continues to be the preferred prime minister over opposition leader Bill Shorten, remaining steady at 39% to Shorten’s 38%. But Abbott’s satisfaction rating has fallen one point to 37%, with his dissatisfaction rating also down one point to 52%. Shorten’s satisfaction rating is up two points to 37%. His dissatisfaction rating is also down one point to 45%.

The popularity of the crossbenchers has fallen slightly. The Greens are down one point to 13%, and other parties are down one point, also to 13%.

The Newspoll survey has a margin of error of three percentage points.