A Manchester Airport spokesman said the Pakistan International Airlines (PIA) flight had been due to land at 1:30pm, but was diverted to London Stansted "where the authorities are investigating".
The spokesman said: "The plane - flight number PK709 - was travelling from Lahore and had 297 passengers on board.
"For further information for friends or family who were due to meet the flight at Manchester please call 0800 140 4007".
More top news
The British public have voted St Paul's Cathedral the country's favourite building ahead of Stonehenge and Buckingham Palace.
A service to remember 'Operation Dynamo', the code name for the mass evacuation of allied troops in 1940, will take place on the beach.
The Bank of England has launched a secret project looking at the economic risk to Britain if the country votes to leave the European Union.