The spokeswoman told the BBC the case is "likely to come up" in the talks that begin Tuesday with Politburo member Li Changchun.
"I think he (Mr. Cameron) will echo what the foreign secretary has said, that we welcome the investigation that is ongoing and we look forward to seeing the outcome of that," the spokeswoman said.
Heywood, who had lived in China for 10 years and spoke fluent Mandarin, was found dead Nov. 15 in a hotel room in the central Chinese city of Chongqing.
Chinese officials initially said he died of "excessive alcohol consumption" but after friends raised doubts the British government requested Chinese authorities reopen the investigation.
There were unconfirmed reports Heywood had died from cyanide poisoning.
Gu Kailai, the wife of disgraced Community Party official Bo Xilai, has been detained on suspicion of murder in the case.
NBC reportedly holds celebs hostage to Jimmy Fallon's show
Aaron Carter is still in love with Hilary Duff