It comes less than 24 hours after two were taken to hospital as a precaution in a separate situation involving suspicious items found in Parliament.
"The Met Police are now investigating suspicious items of mail in Norman Shaw North".
The Met Police said they were called to Westminster just before 10am this morning to reports of another "suspicious package" in the same building as yesterday, Norman Shaw North.
"Specialist officers have been called and the package will be assessed", a police statement said, adding that there were no reported injuries.
Guido Fawkes report Rupa Huq's MP office and other adjacent offices are being evacuated. "We can not provide any more details at this stage", a parliamentary spokesperson said.
The office of opposition Labour MP Mohammad Yasin received the item, while he was not in the room, according to a member of his staff.
London Ambulance Service said it had attended the scene and taken a man and a woman to a nearby hospital as "precaution".
London Ambulance Service said they had initially dispatched a hazardous area response team and after assessing two people at the scene, made a decision to take them to hospital.
It is thought the package was linked to the sick "Punish a Muslim Day" after letters were sent to Muslim families in East London and the Midlands last month.