'has been blockaded' is correct and usable in written English.
You can use it to describe a situation where a place or space is deliberately prevented from being accessed. For example, "The port has been blockaded by the navy ships for the past three days."
Much of the border region has been blockaded by forces loyal to Colonel Qaddafi.
He issued a plea for help for the city of Homs, which has been blockaded and bombarded for more than a year, including a withering new air, artillery and ground assault that began in late June.
The persistence — and fragility — of such attempts was underscored again on Tuesday as hundreds more civilians left the Damascus suburb of Moadhamiya, which has been blockaded for months by the government.
In Gaza, which has been blockaded with western backing and regional complicity since democratic elections five years ago, friends and family tell me the response is a mixture of anger, suspicion and uncertainty about the future.
The Pope spoke after Mr. Castro had compared Cuba's relationship with the United States to that of David and Goliath, complaining that Cuba has been "blockaded and subjected to a veritable economic war" for nearly 40 years.
Urging a speedy reconstruction effort, he announced that Israel was permitting the first truckloads of construction materials to enter the coastal strip, which has been blockaded by Israel and Egypt since before the conflict.
Israel caused an international furore when its commandos shot dead nine protesters on a Turkish ship that was bound with humanitarian supplies for Gaza, which Israel has been blockading.
Since the mid-eighties, clinics across the country had been blockaded, vandalized, and firebombed.
But oil terminals have been blockaded by militiamen demanding a greater share of the revenues for their own regions.
The houses were largely vacant because the ministers have been blockaded in the Hotel du Golf with Mr. Ouattara.
As they met, hundreds of civilians fled rebel-held areas near Damascus that had been blockaded for over a year.
