BANGKOK (REUTERS) - Thai Prime Minister Prayut Chan-o-cha hinted on Tuesday that he has decided which cabinet ministers will be replaced, following comments last month that a reshuffle could take place in September.

The existing cabinet started work in September 2014, four months after the military took power in a coup. Prayut, who as army chief led the coup, was appointed prime minister in August 2014 by a hand-picked legislature.

Since then he has ruled largely unchallenged despite sporadic anti-coup protests, mostly held by student groups, that were quickly snuffed out by police.

His government has, however, come under increasing pressure to deal with Thailand's stumbling economy, something that has put Prayut under mounting pressure to reshuffle his cabinet.

Prayut hinted to reporters on Tuesday that he had decided which cabinet ministers would stay and which would go "a long time ago" but gave not details as to when a reshuffle would take place.

"I changed (the cabinet) a long time ago and it will be done whenever it will be done," Prayut said. "I can change all 53 ministers and when the time is right I will re-shuffle," he added.

More than a year after the junta came to power to restore order after months of sometimes violent street protests, Thailand's economy remains sluggish. The military has been unable to turn around a long-term decline in exports, while domestic demand has remained poor.

Prayut has warned that a cabinet reshuffle may not bring quick change to the economic performance.