
The court said police could seek to extend custody for up to 30 days once the initial detention period expired but not before.
Police have held Veera Musigapong, Natthawut Saikua and Weng Tojirakarn in custody as per court-approved arrest warrants since they surrendered on Tuesday after the end of the red-shirt rally at Government House.
Police sought court permission within 48 hours to continue holding them, as per the Criminal Procedural Code, but the court ruled that the emergency law took precedence.
Defence lawyer Karom Pholthaklang said the court would not hear the custody request before seven days, the mandatory period under emergency law.
Red-shirt co-leader Kokaew Pikulthong said the defence would continue to push for temporary release of the three accused.
"The red shirts will closely monitor the government and will retaliate appropriately for injustice inflicted on the three," he said in a veiled threat in case bail was refused.
Police had prepared to oppose bail applications.
Kokaew anticipates that the emergency measures would be lifted within a few days.
He refused to speculate on the whereabouts of co-leader Jakrapob Penkair, another suspect who remains at large.
The three men were escorted back to their detention cell at Border Patrol Police regional headquarters in Pathum Thani.
The custody hearing took place amid tight security.
Three companies of riot police were deployed to keep peace, while some red shirts - apparently choosing to dress in regular clothes instead of the red-shirt polos with the "Truth Today" insignia - were on hand to provide moral support for their leaders.
Court officials reminded the red shirts not to trespass on court premises.
The three face charges of inflaming crowds into performing violent acts, which went beyond the constitutional right to peaceful assembly.
The three were involved in raising traffic blockades at Victory Monument, Democracy Monument and Sukhumvit Soi 71. Veera took to the rally stage to exhort crowds to to block main roads in the capital. He was also instrumental in setting up the video relay for the fugitive ex-premier.