Poll says ex-president Bush ratings up

US opinions of former president George W Bush are more positive than negative for the first time since 2005, pollster Gallup says.

Some 49 per cent of those surveyed have a positive opinion of the White House occupant from 2001-09, while 46 per cent had an unfavourable opinion.

By comparison, President Barack Obama, in office since January 2009, has an approval rating of 47 per cent in a separate Gallup survey.

When Bush left office, just 40 per cent had a favourable opinion of him, and that fell further amid the economic crisis that began under his administration.

Past presidents tend to become more popular after they leave office, and the other living ex-presidents have much higher favourable ratings than Bush - Bill Clinton (1993-2001) and Jimmy Carter (1977-1981) each rate 69-per-cent approval.

Bush's father, George Bush (1989-1993), stands at 62 per cent in surveys conducted by Gallup in recent years.