Unexpected demands from public officials and the unyielding economics of the real estate boom are putting a squeeze on the massive Miami Worldcenter after the projected groundbreaking was pushed back three months into 2015.

The developer hoped a property tax rebate deal with the city would be hashed out late last week and approved Tuesday, people close to the negotiations said. But unexpected requests from politicians on minority construction hiring delayed an agreement. Meanwhile, talks about public financing for a 3,000-space parking garage on Worldcenter property are on ice.