Li made the remarks while speaking over phone with Malaysian Prime Minister Najib Razak, state-run Xinhua news agency reported.
China is concerned as 154 of the 239 passengers are Chinese nationals. China believes that Malaysia and the US are not providing much information about the latest developments in the probe.
Earlier, Chinese Foreign Ministry asked Malaysia to play a better role in coordinating international search efforts for the plane asking it come up with better ideas and methods.
"The greater the search area becomes, the more difficult the search will be, so we have to come up with better ideas and methods," he said.
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Asked about India, Pakistan and other countries clarifying that the plane has not passed over their airspace, Hong said China has take note of their response.
To a question whether, China has been asked by Malaysia to search its radar data as the plane may have flown to Central Asia flying over Tibet and Xinjiang, he said "Malaysian side raised relevant request. At the moment China will make cooperation as long as conducive to search efforts," he said.
Asked whether China can rule out the plane entering its airspace, Hong said "relevant search operation is going on. We will cooperate with Malaysian side to carry with search efforts".
Hong urged the Malaysian side to provide "comprehensive and correct information" as more countries try to track the Malaysia Airlines flight MH370.
About sections of media asking China to take over the probe as 154 of the 239 passengers are Chinese, he said in accordance with the relevant civil aviation practices, the probe should be conducted by the Malaysian side.
China has updated its embassies in the countries on latest developments.
"As long as there is a slim hope, the Chinese side is ready to make all out efforts in the search," Hong said, adding that China will actively cooperate with Malaysia and all other countries.
China is readjusting its search efforts.
"The focus of China's search efforts is no longer just in the South China Sea," Hong said.
"We have expressed hope that relevant countries helping with the search let us know as they provide information for Malaysia," Hong said.