Falling impairments to boost Investec FY earnings

* Earnings seen up 7 pct in pounds

* Impairments to fall 35 pct

* Shares up 2 pct (Adds details)

JOHANNESBURG, March 20 (Reuters) - South African investment bank and asset manager Investec (LSE: INVP.L - news) said on Thursday its full-year earnings would rise as much as 7 percent after it cut its bad debt charges, sending its shares higher.

The bank's pound-denominated adjusted earnings per share likely grew by between 0-7 percent in the year to end-March. Rand earnings are seen 22-27 percent higher after the South African currency weakened.

"The big impact on us in the period would be the rand. It depreciated by 20 percent in the period," Chief Executive Stephen Koseff told an investor briefing in Johannesburg.

"Against this backdrop, overall our operating profit will be marginally ahead of the prior year in sterling, which translates to approximately 28 percent in rand."

Investec, which is also listed in London, said its struggling Australia arm had dampened an improved performance in Africa and Britain.

Investec is in the process of disposing part of that Australian unit and is also selling Kensington, a UK mortgage business.

Investors have taken kindly to the sales, which they see supporting earnings over the next few years.

Investec shares were up 2 percent at 80.35 rand in Johannesburg at 1220 GMT, bringing gains so far this year to nearly 8 percent.

Earnings, if they come in on the higher end of Investec's guidance, will be just marginally lower than what analysts polled by Reuters had predicted.

Impairments, or bad debt charges, are seen falling by 35 percent, the bank said.

Lending in the first 11 months also declined 10 percent to 16.6 billion pounds, while third party assets under management decreased by 3 percent.

(Reporting by Helen Nyambura-Mwaura; Editing by Ed Stoddard)