"The negotiations have been moved to February 16 for technical reasons," a spokeswoman for the Ministry of Foreign Affairs told AFP by telephone without elaboration.
A subsequent statement from the foreign ministry said the talks would begin at 0600 GMT on Thursday.
The "closed format" negotiations come after representatives from Damascus and the armed opposition failed to make a breakthrough at indirect talks in the city in January.
The meeting -- pushed by key regime supporter Moscow -- is viewed as a warm-up for UN-led negotiations on the protracted war that are due to begin in Geneva on February 23.
While Kazakh officials said they invited both the Syrian government and rebels for the new talks, several of the regime opponents who took part in the previous Astana talks told AFP that they have not received invitations.
Damascus has confirmed it will be represented again by its ambassador to the UN, Bashar al-Jaafari.
Russia is sending presidential envoy Alexander Lavrentiev while Iran said it is dispatching deputy foreign minister Hossein Jaberi Ansari.
UN envoy on Syria Staffan de Mistura said he would not participate personally in the latest Astana meeting but that his office would be represented by a "technical team".
Jordan will also be represented by a "high level delegation" government spokesman Mohamed Momani said.
The Astana initiative has left the West on the sidelines of the latest push to end the war in Syria that has claimed more than 300,000 lives since 2011.
Moscow has invited the US to participate as an observer but the State Department has yet to confirm Washington will be involved.
Talks are likely to focus on bolstering a shaky ceasefire on the ground after Moscow, Tehran and Ankara agreed to establish a "mechanism" aimed at ensuring the truce.
The Geneva negotiations are expected to be wider-ranging, focussing on the key issues that divide the government and rebel sides, including the fate of President Bashar al-Assad.
Russia and Iran have helped turn the tables on the ground with their military backing for Assad, while Turkey has supported rebels fighting to oust the strongman.