A person under the Z category security cover is assigned 22 personnel.
The decision apparently stemmed from the situation Dhankhar faced last month at the Jadavpur University where he had gone to "rescue" Union Minister Babul Supriyo who was heckled by a section of students in the campus.
Dhankhar was stranded for close to an hour in the campus as the radical Left protesters held a sit-in demonstration and even lay prostrate before his vehicle.
It is learnt that following the incident, Raj Bhavan had intimated to the state administration the need to review the Governor's security.
Sources said the Union Home Ministry has informed the state administration of its decision.
From now on, the central forces will be deployed in the security ring around Dhankhar.
"I have never seen anything like this. He is the constitutional head of the state. He can get any form of security he desires. He could have easily told the administration that his security needed to be enhanced," said veteran Trinamool leader and state Panchayat Minister Subrata Mukherjee.
Taking a dig at Dhankhar, he said: "Why he overlooked the administration and went straight to the people in Delhi, only he can say.
"There was no need for the extent of personnel being or that will be deployed by Delhi. I have never heard a Governor feeling insecure," he said.
State BJP president Dilip Ghosh backed the centre on the issue, and said even the Chief Minster did not have faith in the state police.
Ghosh pointed out as Railway Minister (2009-11), Banerjee was provided security by the Railway Protection Force, and continued the arrangement for the first five years of her chief ministerial tenure.
"It will be good if the Centre provides security to the Governor. When the Chief Minister herself doesn't have faith in the police how can they be relied upon for providing security to the Governor?
"We have seen in Jadavpur university how he was insulted, with students blocking his car and kicking it," he said.
Another BJP leader Mukul Roy said even the Governor's life is not secure in the state where "there is no democracy".
"Democracy is being murdered in Bengal. People have no security in Bengal. There is a police raj in the state. The state Governor is invited to official functions only to be insulted. Even the Governor's life is not secure.
"The Central government has taken the right decision by extending its security to him," he added.
Ghosh and Roy themselves are provided security cover by Central paramilitary forces.
Ever since he was sworn in to the top post on July 30, Dhankhar has had a series of run-ins with the state government.
Only two days back, he had alleged that he was "totally blacked out" during the October 11 Kolkata Durga carnival hosted by he state administration and called it "an unusual kind of censorship, reminiscent of the Emergency".
The first stand-off happened over the Governor's visit to Jadavpur University to "rescue" Supriyo, which the Trinamool called "most unfortunate" and "shocking".
Days later, Dhankhar went to Siliguri in north Bengal wishing to hold an official meeting there, only to find state government ministers, officials, as also police officers boycotting the programme.
The Governor also went hammer and tongs at the state administration in connection with the killing of three members of a family in Murhsiadabad district's Jiaganj.
( With inputs from IANS )