Sri Lanka's opposition parties which supported unsuccessful presidential candidate former Army Commander Sarath Fonseka will stage a massive protest in Colombo on Wednesday against alleged harassment to their supporters by the government of President Mahinda Rajapaksa.

Anura Kumara Dissanayake, joint media spokesman for Fonseka, told reporters on Tuesday that a rally will starts at 04:00 p.m. local time after a protest march.

He said that Rajapaksa's win at last week's presidential poll can not be accepted and the election was rigged by Rajapaksa brothers without reflecting the people's will.

Dissanayake said they expect a crowd of nearly 100,000 to converge from all parts of the country to the capital on Wednesday.

Police spokesman I. M. Karunarathna said that security is already strengthened in the aftermath of the presidential poll and they would not hesitate to take stern action against anybody attempting to create trouble in the guise of a political rally.

Rajapaksa won last Tuesday's election for a second term by beating Fonseka with a resounding majority of 57.88 percent to the latter's 40.15 percent.