Thai police on Monday said they were seeking two new suspects over the deadly Bangkok blast, after bomb-making material was found in a second apartment in the city's outskirts.

"The first one is a woman, Wanna Suansan, aged 26," national police spokesman Prawut Thavornsiri said in a televised broadcast, which named a suspect in the case for the first time and showed a photograph of a young woman in a hijab.

"There is also another person living in the room, he is a man, nationality unknown," he added.