The top court had on September 6 ordered demolition of the complex by September 20.
The residents of Maradu flats on Monday said that they are unlikely to leave before October 3 deadline as the "alternate places", where they were supposed to move, were not available.
The residents had themselves promised to move out latest by October 3.
Speaking to the media, the flat residents complained that they didn't receive a proper response when they tried to contact the phone numbers given by district authorities for the arrangement of alternate places to move.
"We were shocked to be told when we contacted the numbers given to us, that there are no such flats to be given. Some of them even threatened us not to call again. If this is the response, then the October 3 deadline will have to be extended," said angry residents.
The 240 families who occupy 356 flats in the four buildings had promised the district authorities on Sunday that they will be moving out latest by Thursday.
The top court had on September 6 ordered demolition of the complex by September 20 for violation of the Coastal Regulation Zone rules.
On Sunday morning, the flat residents began an indefinite protest but called it off at around 3 pm after talks with top district authorities.
Following this demand, Kochi Sub-Collector SK Singh, appointed as a special officer-in-charge of the demolition, will be discussing the matter with the concerned people in the second week of October. He will first finalise the tender for the demolition to one of the more than two dozen companies who have come forward to do the job.
The Supreme Court has directed the Kerala government to disburse Rs 25 lakh as interim compensation to each flat owner within four weeks and recover it from the builders.
The top court also appointed Kerala High Court's retired judge K Balakrishnan Nair to head a three-member committee which will include a technical and civil expert to decide on any increase in the compensation amount, and to oversee the demolition.
According to the affidavit submitted by the Kerala government in the top court, the demolition will be completed in 90 days and the debris will be cleared in another 30 days.