The search of the powerful and ultra-rich Wat Dammakaya temple on Bangkok's outskirts comes after Thailand's junta chief invoked special powers to put its sprawling 1 000-acre compound under military control.
Previous attempts to raid the temple were thwarted after thousands of devotees showed up to defend Phra Dhammachayo, the septuagenarian monk who founded the breakaway Buddhist order in 1970.
The former abbot is believed to be holed up inside the temple, which is famous for its space-age architecture, but has not been seen in public for months.
He is accused of money laundering and accepting embezzled funds worth 1.2 billion baht ($33 million) from the jailed owner of a cooperative bank.
In a day of high drama and stagecraft, thousands of police and soldiers were bussed into the site before dawn on Thursday, locking down roads leading to the vast temple.
The operation followed a sudden order endorsed by junta leader Prayut Chan-O-Cha that gave authorities power to block the entrance.
"The Dhammakaya temple has allowed police and DSI officials to carry out a search inside the temple for the suspect," the head of the DSI, Thailand's equivalent of the FBI, told reporters after an hours-long standoff.
"If (the abbot) thinks he is innocent he should surrender and enter the judicial process," said Colonel Paisit Wongmuang.
Sect supporters are believed to be inside the temple alongside monks, whose mantras could be heard outside the temple walls where columns of back-up police patiently waited.
Speaking to media outside the temple's gate, a Dhammakaya spokesman said he could not confirm whether the wanted ex-abbot was inside.
"I don't know his whereabouts - I haven't seen him in about nine months," said Phra Sanitwong Wutthiwangso.
Temple staff have previously said the leader is innocent but too ill to be questioned by police.
Historically, Thailand's secular authorities have been reluctant to intervene in the affairs of the clergy in the Buddhist-majority country.
But hostility towards the Dhammakaya sect has mounted in recent years, with critics from the mainstream Buddhist establishment accusing the temple of promoting a pay-your-way to nirvana philosophy.
The controversy is also fuelled by speculation that the temple has links to Thaksin Shinawatra - the ex-premier who was ousted in a 2006 military coup and lies at the heart of the kingdom's rancorous political divide.
The administration of his sister Yingluck, who was also prime minister, was toppled by the military again in 2014.
The temple denies any political affiliations and says it has become a pawn in a battle that pits the Shinawatras and their rural supporters against Bangkok's army-allied elite.
Aided by a sophisticated PR operation, the sect has enjoyed a meteoric rise over the past three decades, raising tens of millions of dollars and opening outposts around the world.
It is also famous for hosting visually-stunning mass gatherings of orange-robed monks on Buddhist holy days - events derided by critics as a display of the sect's "cultish" approach.
Last week Thailand's new king chose an octoganerian abbot to become the country's new top monk, ending a three year stalemate over the position and passing over a Dhammakaya-linked cleric who was next-in-line for the job.