LAGOS (Reuters) - Nigeria will shut its main international airport in the oil producing Niger Delta at Port Harcourt for at least four months' repairs later on Friday, the aviation agency said.

The Nigerian Civil Aviation Authority said the emergency shutdown was required to rehabilitate the runway and build a fence around the facility.

"The airport is being closed down for safety reasons , We hope that the rehabilitation work will be completed and the airport reopened in December," a spokesman said.

"They have been directed to close it down at sunset today."

Port Harcourt is the largest city in the delta, and several Western oil companies including Royal Dutch Shell have large offices there.

Lufthansa and Air France fly there direct from Europe.

Safety standards at Nigerian airports have come under close scrutiny since President Olusegun Obasanjo ordered urgent reforms in December after two plane crashes that killed more than 200 people last year.

One of the crashes on December 10 was at the Port Harcourt airport where 106 passengers, many of them school children, were killed. Some commentators said that lives could have been saved if the fire trucks at the airport had had access to water.

The disaster came seven weeks after another airplane crashed near Lagos, killing 117 people.

In July last year, an Air France plane with 196 passengers on board ploughed into a herd of cattle on the runway. No humans were killed, but authorities blamed the accident on the lack of a perimeter fence.

The runway lighting and firefighting facilities at the airport will also be overhauled during the shutdown, the spokesman said.

The NCAA said all domestic flights to Port Harcourt will be diverted either to the smaller delta city of Warri, the southeastern city of Owerri or to Calabar in the southeastern corner of the country.

International flights will be diverted to Nigeria's two main airports in the commercial hub of Lagos and the inland capital Abuja, the aviation agency said

Satellite Picture of Port Harcourt
from Google Earth