SANTIAGO (Reuters) - Chilean cabinet chief and Interior Minister Jorge Burgos resigned on Wednesday, the government said, after a series of policy disputes with other government officials and as the popularity of President Michelle Bachelet plumbs all-time lows.

Burgos, a member of the Christian Democrat (DC) party, part of Bachelet's New Majority governing alliance, had butted heads with fellow ministers over labor policy reforms and the government's crime-fighting agenda.

The government said Burgos presented his resignation due to "personal reasons" and has replaced him in the post with fellow Christian Democrat Mario Fernandez Baeza, who had up until now served as ambassador to Uruguay.

The government issued its statement confirming the resignation originally revealed by congressman Matias Walker, who also serves as vice president of the Christian Democrats.

"It took us by surprise and we regret it very much," Walker told reporters.

Bachelet's popularity dropped to 24 percent in May from 29 percent the previous month, returning to last year's all-time low, according to a survey by pollster Gfk Adimark.

She is about midway through a term that began in March 2014 and has seen her previously high approval ratings weakened by financial scandals and anger over a stagnant economy.

(Reporting by Antonio De la Jara and Felipe Iturrieta; Writing by Hugh Bronstein & Anthony Esposito; Editing by David Gregorio)