She cited the Palestinian political split, with Western-backed moderate Abbas and the Islamic militant Hamas running rival governments in the West Bank and Gaza, as well as the more hawkish positions of Netanyahu, compared to his predecessor.
"But I think there is a recognition of the urgency," she said. "If we don't move fast and decisively, things could fall apart."
Hamas, which seized Gaza from Abbas in 2007, has dismissed the new talks, and the militant movement's spokesman Sami Abu Zuhri on Monday rejected the notion that Abbas is representing the Palestinians at the talks.
Resuming negotiations "is a dangerous step and the only beneficiary is the occupation (Israel), which uses it as a cover for its continued crimes," Abu Zuhri said.
Hamas wants to establish an Islamic state in all of historic Palestine, including what is now Israel. Hamas has raised the possibility of long-term cease-fires under some circumstances, but has made clear it would not consider a partition deal to be the end of the Israeli-Arab conflict.
The resumption of talks comes after six months of shuttle diplomacy by Kerry, and Israel's agreement to release veteran prisoners was key to the secretary's success.
The Israeli Cabinet decision was welcomed by Palestinians, and drew some angry reactions in Israel.
The fate of Palestinian prisoners is an emotional issue on both sides. Palestinians tend to view the prisoners as heroes who sacrificed for the struggle for statehood, while many Israelis see them as cold-blooded killers.
"The murderers will be released," read the front-page headline in Israel's daily newspaper Yedioth Ahronot on Monday.
In another sign of possible momentum, Martin Indyk, a former US ambassador to Israel who directs the foreign policy program at the Brookings Institution think tank in Washington, is expected to be named as the new US envoy for Middle East peace, possibly as early as Monday, a source familiar with the matter said.
China has always been willing to see a peaceful resolution to the issue. Chinese Foreign Ministry spokeswoman Hua Chunying said earlier this month in a news conference that China welcomes the resumption of peace talks and appreciates the joint efforts from the related sides.
China hopes that the two countries can overcome their difficulties and achieve substantial agreements as soon as possible, she said.