MOSCOW (Reuters) - Russia's finance ministry on Wednesday said it had extended a subsidised mortgage programme for families until 2030 following an order from President Vladimir Putin.

The programme's extension, which entitles families with young children to obtain mortgages at 6% interest, was a key part of Putin's social pledges in the run-up to his re-election in March.

The Bank of Russia's key interest rate is 16%, but is widely expected to be raised on July 26, possibly as high as 18%.

The finance ministry said in March that extending the preferential mortgage programme would cost an extra 1.5 trillion roubles ($17.2 billion) over the next six years.

On Wednesday, the ministry said 223.8 billion roubles had been originally set aside for funding in 2024, but that another 66.2 billion roubles would be required.

"Additional expenses for the family mortgage programme will depend on the level of the Bank of Russia's key rate," the ministry said in a statement.

($1 = 87.4000 roubles)

(Reporting by Darya Korsunskaya and Alexander Marrow; Editing by Mark Trevelyan)