Siam Cement is expected to report a fall in net profit for the second quarter hurt by weak results of its core petrochemical business.

Citigroup forecast Siam's net profit to fall 42 per cent to THB4.35bn for the April-June quarter, YoY, according to a Reuters report.

"First-half estimated profit should come at 34 per cent of consensus fiscal year forecast, possibly leading to further earnings downgrades and a cap on the share price in the medium term," it said in a report.

Citigroup maintained its 'buy' rating on the stock, citing strong domestic consumption supporting Siam's cement and building material businesses, with a target price of THB388.

"Non-chemical business should partly offset chemical weakness until the next cyclical upturn," it said.