* More talk than action expected at summit

* Zuma to stand firm on economic policy

By Peroshni Govender

JOHANNESBURG, Nov 12 (Reuters) - South African President Jacob Zuma's meeting with his trade union and communist allies from Friday may produce more rhetoric than substance despite their push to have him shift economic policy to the left.

Zuma's ruling ANC has suggested that it won't cave in to pressure from COSATU, the trade union federation, and the South African Communist Party to boost government spending.

In one significant sign of that, the African National Congress (ANC) has backed Trevor Manuel's leadership of the government's National Planning Commission, dealing a blow to union allies who want the former finance minister sidelined.

Zuma is no longer as dependent on the unions and the communists who helped his rise. So when he sits across from them at the three-day meeting, their first such gathering since the April election, the president won't have to take calls for a leftist policy shift as seriously.

He is unlikely, though, to merely rebuff their concerns and may recommit to debate, quietening the most vocal figures.