Talking to reporters here, Mr Thackeray said his party will be firmly in support of the BMC commissioner. The Shiv Sena is in power in the BMC for the past two decades.
"The civic authorities should first thoroughly confirm that the premises they are going to demolish are not complying with rules and regulations and then take action no matter how influential the owners are. Shiv Sena will be in support of the civic administration," Mr Thackeray said.
"BMC should not succumb to political pressure while carrying out the demolition of illegal pubs and eateries," the Sena President said.
The Mumbai civic body has started demolition of illegal constructions or alterations at pubs and eateries after a deadly fire at the rooftop pub 1 Above in Kamala Mills compound claimed 14 lives on December 29.
Mr Thackeray said it reflects poorly on the police and the state's home department (which is headed by Chief Minister Devendra Fadnavis).
"Why the accused can't be traced and arrested yet," Mr Thackeray questioned.