An Egyptian Foreign Ministry statement on Saturday did not deny that such contacts took place but asked whether the purpose of the Iraqi remarks was to "avoid responsibility ... and justify a tragedy".
Foreign Minister Ahmed Aboul Ghait said in the statement that now was the time to concentrate on catching those who killed the ambassador-designate, abducted in Baghdad a week ago, and to respect the feelings of the Egyptian people.
It quoted Iraqi government spokesman Laith Kubba as saying that Baghdad was investigating whether al-Sherif, the head of the Egyptian diplomatic mission, was in touch with anti-US fighters.
On Thursday, the day Egypt confirmed that al-Sherif was dead, Iraqi Interior Minister Bayan Jabor repeated his view that some foreign diplomats were in contact with anti-government groups. He declined to say to which envoys he was referring.
The Egyptian government has come under fire at home for its handling of al-Sherif's kidnapping. Critics have said it did not do enough to protect the envoy, that it was too slow in making contacts to save him and that it was too hasty in sending such a high-ranking diplomat to an insecure country.
The incident also appears to have driven a wedge between Cairo and Baghdad, through the Egyptian government says it will not allow the killing to disrupt its efforts to help Iraqis.
Egyptian envoy Ihab al-Sherif
went missing on 3 July
Abou Gheit said: "News agencies bring us remarks ... which raise questions about their meaning, import and purpose and whether the intent is to avoid responsibility or merely to repeat rumours and justify a tragedy."
He said a serious security effort was needed in Iraq to catch the killers and "to bring back confidence in the possibility of restoring security and stability in Iraq".
"The assistant foreign minister in charge of Arab affairs has been asked to take up these Iraqi remarks with the Iraqi charge d'affaires in Cairo," the statement added.
An Egyptian researcher in strategic affairs, Major General Salah Saleem, told Aljazeera on Saturday that the Iraq government was at fault for not providing more security. He also blamed the Iraqi government for failing to set a timetable for the replacement of US-led troops with Iraqi forces.
Egypt has decided to reduce the size of its diplomatic mission in Iraq in response to the killing.
The al-Qaida organisation in Iraq claimed responsibility for killing al-Sherif, saying he was an "enemy of God" serving a tyrannical government allied to Jews and Christians.