Al-Sadek said Sudan was working hard not to let the expulsion of the officials hamper relations with the European Union or Canada.
The European Commission confirmed Kent Degerfelt, its envoy to Sudan, had been ordered to leave the country and the Canadian government said Nuala Lawlor, its charge d'affaires, had also been asked to leave.
Ali Karti, the Sudanese minister of state, said that the two diplomats had been holding what the government regarded as unacceptable contacts with opposition leaders.
"It is necessary now to send a clear message to whoever thinks that the kind of relationship between Sudan and the United Nations, and the international community in general, is that of submissiveness," Karti told the Sudan Tribune newspaper.
The London-based Arabic daily Al-Hayat quoted a Sudanese source as saying that the two diplomats had been "holding meetings and contacts with rebels in Darfur and opposition figures in Khartoum and NGOs which the government considers a front for dissidents".
The government had "indirectly warned the diplomats over the issue twice before", the paper said.
|In 2006, Khartoum expelled Jan Pronk for|
criticising Sudan's actions in Darfur [AP]
Canada has demanded an explanation from Khartoum.
"We have asked them why they expelled our charge d'affaires," said Rodney Moore, a foreign ministry spokesman.
He said Lawlor had "defended our values of freedom, democracy, personal rights and the rule of law".
Degerfelt, who was on holiday in Italy at the time of his expulsion, said he was in contact with the Sudanese authorities and would "try to sort this out in a constructive spirit".
He reportedly told the Retuers news agency by phone: "I have been in Sudan for five years and I have always worked for the good of Sudan and its people and that is why I believe that maybe there is some sort of misunderstanding somewhere."
In the US, the White House said it hoped the expulsions were not an attempt to sidetrack international efforts to end the violence in Darfur, which Washington has called genocidal.
Gordon Johndroe, a White House spokesman, said: "The Sudanese have a history of doing this sort of thing to try and thwart the will of the international community."
He said the US hoped Sudan was "still planning on complying with their obligations to the UN Security Council".
Ban Ki-moon, the UN secretary-general, is expected to travel to Khartoum early next month to thrash out details of the deployment of up to 26,000 peacekeepers to the troubled Darfur region.
Fighting in the western Sudanese region broke out in February 2003 when minority tribes used force to demand an equal share of national resources.
The action prompted a violent response from government forces and proxy fighters, know as the Janjawid.
In October 2006, Khartoum expelled Jan Pronk, the UN envoy, for criticising Sudan's actions in Darfur.
At least 200,000 people have been killed and more than two million have been displaced by the conflict and famine in Darfur, according to estimates by the UN.