UPDATE 2-South Africa oil workers' strike could hit refineries

* Strike over wages planned for Thursday

* Oil firms have secured fuel supplies

* Shell, BP, Chevron and Sasol plants may be hit (Adds employer body's comments, details)

By Wendell Roelf

CAPE TOWN, July 27 (Reuters) - South African energy workersplan to strike indefinitely from Thursday over pay, the unionrepresenting them said, a stoppage that will potentially hit oilrefineries of companies including Shell, BP Chevron and Sasol.

Around 23,000 workers in the petrochemical andpharmaceutical sectors are expected to take part in the strike,Clement Chitja, head of collective bargaining, the Chemical,Energy, Paper, Printing, Wood and Allied Workers Union(CEPPWAWU), said on Wednesday.

"We want a deal of 9 percent in one year," Chitja toldReuters. He said employer associations were offering smallerincreases and looking for multi-year agreements.

The National Petroleum Employer's Association (NPEA) said aweak economy at home and weak global oil prices meant they couldonly offer a 7 percent raise this year, and an April CPI plus1.5 percent improvement factor the following year.

"In light of the economic conditions and where the industryis, given the global price decline, we believe our offer isreasonable and are hoping we will find each other," ZimiseleMajamane, NPEA's deputy chairman, told Reuters.

He said they were assured by member companies thatcontingency measures were in place to see the strike through,"But it all depends on how long it takes and how intense it is."

Shell and BP jointly operate the largest refinery in SouthAfrica, the 190,000 barrel-a-day plant along the east coast. Chevron, Sasol and PetroSA run smaller refineries.

South African petrochemical giant Sasol said it had madearrangements to ensure minimal disruptions to customers. Shell,BP and Chevron were not immediately available to comment.

The country is a net importer of refined petroleum productsand long strike could lead to shortages. The strike also comesas the country votes next week in hotly-contested municipalelections.

The stoppage could also further damage the economy, which isforecast by the central bank to stagnate this year afterexpanding 1.3 percent in 2015.

Higher-than-inflation wage increases, which are being soughtthis year in wage negotiations in the mining, petroleum andmanufacturing sectors, have been flagged by policymakers as adanger to an already weak economy.

Inflation stood at 6.3 percent in June, above the centralbank's target range of 3-6 percent.

($1 = 14.3024 rand) (Reporting by Wendell Roelf; Editing by James Macharia and JaneMerriman)