(Adds details) JOHANNESBURG, June 22 (Reuters) - South Africa's...

(Adds details)

JOHANNESBURG, June 22 (Reuters) - South Africa's equity market slumped and the rand strengthened somewhat on Wednesday after a bigger-than-expected inflation spike in May raised concerns the Reserve Bank may continue to tighten its policy.

South Africa's headline consumer inflation ZACPIY=ECI , ZACPI=ECI quickened to 6.5% year-on-year in May, the highest since January 2017, Statistics South Africa said. Analysts polled by Reuters had predicted inflation would pick up to 6.2% in annual terms from 5.9% in April.

May's reading breached the South African Reserve Bank's (SARB) target range of between 3 and 6% for the first time in over five years.

"GDP levels back at pre-Covid levels coupled with evidence of building second round price pressures means that the SARB will likely favour a more frontloaded hiking cycle," Jeff Schultz, Senior Economist at BNP Paribas South Africa said.

Retailers have recently warned that rising interest rates will negatively impact consumer spending as already financially constrained consumers battle food and fuel price pressures.

"Poor consumer spending will in turn dampen economic growth, along with many other idiosyncratic factors," said Casey Delport, Investment Analyst at Anchor Capital.

The All-share index .JALSH dropped 1.55% to 65,712 points. The blue-chip index of top 40 companies .JTOPI sunk 1.59% to 59,414 points.

Among retailers feeling the pain, Walmart majority-owned Massmart MSMJ.J fell 2.94% to 35 rand, while grocery chains Shoprite SHPJ.J and Woolworths WHLJ.J fell 1.72% and 1.52% respectively.

The biggest decliner on the bourse was PPC PPCJ.J , which tumbled 19.10% to a more than one-year low after the cement maker said its full-year profit from continuing operations would swing to a loss.

In the currency market, at 1607 GMT, the rand ZAR=D3 traded at 15.90.50 against the dollar, 0.09% stronger than its previous close.

It pared gains clocked during the day after the inflation data as Federal Reserve Chair Jerome Powell said the U.S. central bank is "strongly committed" to bringing down inflation.

Investors are continuing to assess how worried they need to be about central banks potentially pushing the world economy into recession as they attempt to curb inflation with interest rate increases.

Higher rates in developed markets tend to drain capital from riskier emerging markets.

The yield on government's benchmark 2030 bond ZAR2030= rose 3 basis points to 10.135%.