A British Airways flight made an emergency landing in Romania amid reports four people suffered possible smoke inhalation.

The BA603 flight travelling from Istanbul to London requested to make a landing at Bucharest Henri Coanda International Airport at 5.50pm local time on Thursday.

The aircraft carrying 142 passengers eventually landed at 6.14pm with emergency response and medical crews boarding the plane, according to the airport.

Romania's Ministry of Health said in a statement that the 'presence of smoke was confirmed' immediately after the plane landed.

'Four people are in poor health, possibly being smoke-intoxicated, and are receiving medical assistance on site,' the ministry said.