Jan 29 (Reuters) - National Australia Bank said on Friday it would buy the remaining 81.7% stake in online banking platform 86 400 Holdings for up to A$220 million ($168.9 million).

NAB currently owns an 18.3% stake in 86 400 Holdings, which has more than 85,000 customers and A$375 million of deposits.

($1 = 1.3028 Australian dollars) (Reporting by Sameer Manekar in Bengaluru; Editing by Aditya Soni)