Last week, Qatar disclosed a list of 13 demands issued by the group, including downgrading ties with Iran, a regional rival of Saudi Arabia, ending support for Islamist groups and shutting down the Doha-based broadcaster Al-Jazeera and its channels.
On June 22 they presented a list of 13 demands and gave Doha 10 days to comply.
Kuwait reportedly requested that the four countries grant the Gulf state a two-day extension but did not mention anything related to where Qatar stands regarding the demands.
Qatar is hours away from facing sanctions, unless it accepts demands from its neighbours which are accusing Doha of supporting terrorism.
Kuwait's ruler Sheikh Sabah Al-Ahmad Al-Jaber Al-Sabah reportedly informed the four countries that Doha had confirmed to him that it would send on Monday its official hand written response to the list of demands it received on June 23.
Foreign ministers from the four countries will meet in Cairo to discuss the situation on Wednesday, Egypt said.
Among the potential further steps the countries could take against Qatar would be to suspend it from the six-nation Gulf Cooperation Council (GCC), which is closely allied to the United States.
It is unclear what consequences Qatar will face if it misses tomorrow's deadline.
Late on Sunday, before the postponment, US President Donald Trump spoke to the leaders of Saudi Arabia, Qatar and the Crown Prince of Abu Dhabi in the UAE separately to voice his "concerns about the ongoing dispute". Further demands insist that Qatar cut ties with all "terrorist organizations", including the Muslim Brotherhood and Lebanon's Hezbollah.
The AP says that the White House "urged unity and reiterated the importance of stopping terrorist financing and discrediting extremist ideology".
While Trump has largely echoed the concerns of the blockading nations, his secretary of state, Rex Tillerson, has called for an end to the blockade, which he said has hurt USA interests in the region.