Shortly after arriving in the country, Moreno-Campo told a news conference that he hoped his investigations would send a signal to 15 African countries that are to hold elections in the next 18 months to discourage them from violence.
Moreno-Ocampo was also due to meet activists of non-governmental organisations, the business community, religious leaders, the media and government officials.
He was expected to use a town hall event to explain to Kenyans the work of the ICC and the process of the investigations he will carry out.
Al Jazeera's Andrew Simmons, reporting from Nairobi, said there were reasonable grounds to start the investigations.
"There has been a commission here [in Kenya] which a lot of people gave evidence to," he said.
"There was a list of names. There has also been a human rights report which named various people ... He [Moreno-Ocampo] is saying he has no specific names as suspects yet [but] he intends to go ahead ..."
But our correspondent said the problem is that "no one is sure of the Kenyan security system", adding that a "lot of people who think they may be witnesses or are perceived to be witnesses are living in fear".
'There is a lot of doubt about [the security system], so witness protection is key," Simmons said.
Weeks of violence that followed Kenya's 2007 general election left more than 1,133 people dead, forced 400,000 to flee their homes, and brought Kenya to the brink of civil war.
The political and humanitarian crisis erupted after Mwai Kibaki, the president, declared victory after the poll amid accusations by opposition supporters that the election had been rigged.
Kenya has shown little willingness to prosecute those responsible for the violence, but has agreed to provide the ICC with confidential information about the unrest.
Mark Ellis, executive director at the International Bar Association, earlier told Al Jazeera that "the ICC provided an opportunity for Kenya to undertake their own investigation and prosecution, but they were not able to do that.
"It is morally and legally right for the International Criminal Court now to undertake this first step and that is the investigation into the crimes that were committed in Kenya."
Moreno-Ocampo has said that Kenyan political leaders organised and financed the attacks against civilians.
"President Kibaki's and Prime Minister [Raila] Odinga's commitment to justice and to co-operation with the ICC is crucial," he said earlier this month.
"The whole international community is with the Kenyans, all Kenyans must come together and use the law and justice as a basis for their common future. The common goal is to ensure there is no repeat of violence in the 2012 elections."
The ICC says that a majority of its judges have responded positively to Moreno-Ocampo's request to undertake the investigation, saying "the information available provides a reasonable basis to believe that crimes against humanity have been committed on Kenyan territory".