Seema Malhotra, 43, who had resigned as shadow chief secretary to the Treasury along with a number of her party colleagues last month, has called on Speaker Jon Bercow to launch an official investigation into the incident.
The MP for Feltham and Heston has claimed people from the Opposition leader's office used digital keys to open her office door.
"I have discovered that members of staff working for John McDonnell [shadow chancellor] and Corbyn have gained unauthorised entry into my office in Parliament. The implications of this are extremely serious.
"Furthermore, my staff, including an intern, who have always been courteous and open, have felt harassed, intimidated and insecure.
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"I have made a formal complaint to the Speaker of the Commons and to Corbyn, and requested an investigation into how this could have happened," the statement added.
Since the police search of newly-appointed work and pensions minister Damian Green's office when he was an Opposition lawmaker back in 2008, it has been accepted that only a search warrant can justify an entry in a parliamentary office without the wishes of an MP.
Aspokesperson for Corbyn said accusations that Karie Murphy - the Labour leader's office manager - had intimidated anyone were "untrue".
He said Murphy had been checking to see if the office had been vacated by Malhotra following her resignation.
He said: "She accessed the office in question to confirm when it would be vacated. It is a month since Malhotra resigned as shadow chief secretary to the Treasury, and the office is intended for the person holding that position."
It comes after more than 40 female Labour MPs wrote to Corbyn earlier this week saying he had failed to do enough to prevent "disgusting" threats against members.
The group of female MPs, including former shadow ministers Heidi Alexander, Paula Sherriff and Kerry McCarthy, say intimidation has been carried out in Corbyn's name.