Prime Minister Yingluck Shinawatra appears uncertain of the army's stance on the anti-government rallies after it set up a temporary headquarters at the 1st Infantry Regiment.
The army has insisted it will keep out of the street protests.
However, a source close to the premier said Ms Yingluck is beginning to question what the army will do if the demonstrations escalate further.
"Eventually soldiers will choose the nation. The army does not take sides, but it may need to do something if it faces pressure or a dangerous situation," the source said.
Given the fragile political climate, the government needs to watch the army's move carefully, the source said.
However, Ms Yingluck and army chief Prayuth Chan-ocha have a good relationship and the relocation of the headquarters is only temporary.
The headquarters moved to the 1st Infantry Regiment (Royal Guard) on Vibhavadi Rangsit Road on Monday, when Democrat-led demonstrators rallied in front of the army's base on Ratchadamnoen Avenue.
Though the rally-goers left later that day, Gen Prayuth and senior military officers have continued working at the 1st Infantry Regiment without setting a return date, the source said.
Its move, together with the army's past involvement in coups, has stirred speculation about what it may be planning, the source added.
However, defence ministry spokesman Thanathip Sawangsaeng on Tuesday denied there is any hidden motive behind the relocation. The officers will return to their Ratchadamnoen headquarters when the situation returns to normal, Col Thanathip said.
Traffic congestion around the Ratchadamnoen base affected officers' travel to their workplace and they had to enter through the back gate because demonstrators led by the Dhamma Army occupied the area in front of the normal entrance, deputy army spokesman Winthai Suwari said.
The Dhamma Army is a key supporting group of the People's Democratic Force to Overthrow Thaksinism, one of the three main anti-government groups.
The government has decided not to break up the demonstrations, but will enforce the law to keep order.
"The government will not disperse them. Let them occupy the areas and wait until people get bored," said a security source, citing the conclusion of a special meeting of cabinet members on Monday after rally-goers seized offices in the Budget Bureau and Foreign Affairs Ministry.
Col Thanathip, meanwhile, called on protesters to consider whether they still consider their actions peaceful.
He warned them against supporting any act that breaks the law.