The delay, announced by the Obama administration, allows insurance companies an additional month to set their 2015 rates on the exchanges, The Hill reported Friday.
Alexander, the top Republican on the Senate Health, Education, labor and Pensions Committee, said the delay is a blatant political move by President Barack Obama.
"The only American consumers this change will help are Democratic politicians who voted for Obamacare, because it delays disclosure of some of the law's most insidious effects until after the election," he said in a statement on his official website.
The change means the enrollment period would be delayed until Nov. 15, 2014, so people who get health insurance under the law will not know their 2015 premiums until after they vote.
Democrats have pressured Obama to delay mandates under the law because of the troubled rollout of websites for healthcare exchanges.