By Jennifer Hill, Personal Finance Correspondent

LONDON (Reuters) - Ailing Northern Rock has upped its efforts to attract new savers, while retrenching from the mortgage market, since liquidity woes plunged it into crisis three months ago.

Britain's fifth-largest mortgage bank has made wide-scale changes to its retail product offering, many of which have taken place in the last fortnight.

The bank is offering savers a loyalty bonus and has hiked rates on a range of savings accounts to try and stem an exodus of savers and bolster funds held on deposit.

At the same time, it has withdrawn mortgages, loans and a credit card, and increased borrowing rates to dissuade new customers.

News that Northern Rock was forced to call on the Bank of England (BoE) for emergency funding in mid-September, after failing to raise funds on wholesale markets, sparked the first run on the savings of a major British bank in 140 years.

Customers queued outside branches to withdraw their money, and the central bank and the Treasury were forced to guarantee new and existing deposits to curb the outflow.

Northern Rock has subsequently vied to make its savings products more attractive.

It is giving those who held one of its savings accounts on December 1 a bonus of 0.5 percent gross annual interest for the months of January and February, if they keep their money invested until March 1, 2008.