WASHINGTON — Sen. John McCain yesterday opened a probe into the practice of senior officials in the Obama administration using secret e-mail accounts to conduct public business.

“Four years ago, you pledged to usher in a new era of government transparency. Since then, however, your administration has habitually circumvented congressional oversight,” McCain said in a testy letter to Obama.

He noted that former Environmental Protection Agency head Lisa Jackson sent thousands of internal e-mails under the name “Richard Windsor.”

He also complained that Justice Department appointee Thomas Perez, the nominee for secretary of labor, had used a personal e-mail account 1,200 times since 2009, but had only turned over 34 e-mails to a House committee.

McCain, a member of a Senate investigative panel, asked Obama to answer eight questions including: “How widespread is the use of secret e-mail accounts within your administration?”

White House Press Secretary Jay Carney has called the practice “consistent with prior administrations of both parties.”