PetroKazakhstan said on Wednesday it intended to close the deal with CNPC later in the day.
Lukoil had asked the court in the Canadian province of Alberta to block the CNPC deal because it said it had pre-emption rights to buy a 50 percent stake in Turgai Petroleum, a 50/50 joint venture between Lukoil and PetroKaz.
It said it would match CNPC's offer if the court decided not to approve CNPC's bid.
No comment was immediately available from Lukoil. Turgai produces around a third of PetroKaz's total output of 150,000 barrels per day and Lukoil has said it is ready to buy the other 50 percent in Turgai for $700 million.
Kazakhstan, which this month signed a memorandum with CNPC on buying a 33-percent stake in PetroKazakhstan for $1.4 billion, will approve the take-over deal if all the terms agreed with the Chinese firm are met, a senior Kazakh official said.
"If all the terms (of the KazMunaiGas-CNPC memorandum) are respected, it will be all OK," Kazakh Energy and Mineral Resources Minister Vladimir Shkolnik told Reuters by telephone from Moscow. "We will give the deal our go-ahead then."
Earlier this month the Kazakh parliament hastily adopted amendments to its subsoil legislation allowing the state to pre-empt sell-offs of "strategic assets", such as foreign-held stakes in oil firms, and the new law has alarmed some investors.
Kazakhstan's main objection to the deal was that it wanted control of the Shymkent refinery, the most modern of only three such plants in the country.
"We're talking about Kazakhstan's participation... in running and controlling the Shymkent refinery," Shkolnik said, repeating a preliminary agreement with CNPC to run the plant on a parity basis.
The state wants to control Shymkent because it aims to curb fast rising fuel prices in the sprawling nation of 15 million.
The government has in the past repeatedly accused PetroKazakhstan of monopolising the local market for oil products and said more recently that the Canadian firm was seeking a "secret" deal with CNPC without informing it.
PetroKazakhstan is facing a fine of more than $500 million ordered by the Kazakh government for "monopoly profits".
CNPC has assuaged Kazakh concerns by agreeing to sell the government 33 percent of PetroKazakhstan, a deal that includes sharing control of the refinery and a co-operation agreement with state energy firm KazMunaiGas.