S.Africa to rebase GDP, revise growth data

* Stats agency to benchmark, rebased GDP data

* Will lead to revisions of growth since 2002

* New survey to include previously uncaptured activities

JOHANNESBURG, Nov 6 (Reuters) - South Africa's statistics agency has rebased its gross domestic product survey and added previously excluded activities that could lead to revisions of past economic growth numbers, officials said on Friday.

Joe de Beer, executive manager for national accounts at Statistics South Africa, told reporters the GDP data to be released later this month would give a more accurate picture of the size of and conditions within Africa's biggest economy.

National accounts would be benchmarked and re-based to the year 2005 from 2000 as part of a regular 5-yearly revision.

Previous rebasings have led to big increases in the size of the economy -- 13.7 percent a decade ago and 3.5 percent for data released in 2004 -- and on both occasions growth was revised upwards.

However, those changes were also affected by other substantive changes that were made to the survey and the revision may not be as large this year.