"Building a climate of reconciliation that is free from conflict is much more important than amending the constitution in order to strengthen the country's economy and security. Constitutional amendment is also important but not urgent. It would not be good if amendments lead to a conflict," she said.
The part of the constitution that could be amended would be a 2007 charter that came out of a military coup, The Bangkok Post reported.
Yingluck said a working committee has been set up to hold a referendum before the amendment.
The prime minister said a referendum would be time consuming and if it is done the amendment process may not be done by the end of 2013.
"This matter [constitutional amendment] will not lead to a state of chaos as happened in Egypt because the government has the objective of pushing the country forward," Yingluck said.