Security authorities are confident of their ability to handle anti-government protesters who will attempt to derail the parliament debate of an amnesty bill sponsored by Pheu Thai Party MP Worachai Hema on Wednesday.

National police chief Adul Saengsingkaew and commander of the Metropolitan Police Bureau Kamronwit Thoopkrachang briefed the cabinet at Government House on the eve of the showdown expected on Wednesday.

Tensions rose on Tuesday after Pheu Thai members and government whips reaffirmed their plan to put the bill on the House agenda, despite a call from the Bhumjaithai Party to withdraw the legislation, to avoid any potential clashes.

A cabinet source said the two top officers are adamant that security authorities can cope with demonstrators due to march on parliament.

Police have already sealed off areas leading to parliament and Government House by deploying 38,910 officers from 20 units. Dusit, Prompap Sattrupai and Phra Nakhon districts are subject to the Internal Security Act (ISA) until Saturday, to give authorities more flexibility in enforcing peace and order.

Pol Gen Adul and Pol Lt Gen Kamronwit have assessed the situation, and claim the turnout of the protesters will not be unmanageable, and could be hampered by adverse weather conditions, the source said.

The two did not rule out the worst case scenario in which demonstrators could surround parliament. But the situation is under control, the source quoted them as telling the cabinet, including Prime Minister Yingluck Shinawatra.

The government will face protests from two key groups – the People’s Democratic Force to Overthrow Thaksinism (Pefot), who are camped at Lumphini Park, and supporters of the Democrat Party, who have converged at a sports ground under Urupong expressway on Phetchaburi Road in Ratchathewi district, not far from parliament.

Deputy Commerce Minister Nattawut Saikuar, a key leader of the United Front for Democracy against Dictatorship, told a cabinet meeting that there was no need to be concerned about Pefot, because the group lacked the leadership to pose a threat, the source said.

Pefot leaders announced that its protesters will gather at the park at 9am on Wednesday.

Thaikorn Polsuwan, Pefot coordinator, said further strategies will be disclosed on Wednesday and asked protesters to be ready to move.

Mr Thaikorn refused to reveal whether the Pefot group would join the rally backed by the opposition party.

The prime minister on Wednesday called on protesters to stage a peaceful rally in order to maintain law and order.

Pheu Thai spokesman Prompong Nopparit said the Worachai bill will be the only one debated on Wednesday, with no other amnesty legislation taken up for joint consideration.

Mr Prompong said the Pheu Thai Party has set up a war room to follow the protest situation and would coordinate with security officials to make sure that all MPs can enter parliament for the debate on the bill.

The Bangkok Metropolitan Administration (BMA) has ordered nine schools to close for three days between Wednesday and Friday because of the planned rally, Bangkok governor Sukhumbhand Paribatra announced on Tuesday.

The nine are Wat Thammapirataram, Wat Benjamabopit, Wat Chansamosorn, Wat Thewaratkunchorn, Wat Saman Namborihan, Wat Pracha Rabuetham, Wat Sawat Wari Simaram, Wat Ratchaphatikaram and Sukhothai school.

Mr Sukhumbhand cited security concerns as the reason for the closure of the schools.

He said the BMA will follow the political rally through closed-circuit television cameras at its CCTV control centre.

The BMA’s Security Operations Command at city hall will serve as the main centre for following and assessing the situation and coordinating with public agencies concerned.

The Medical Department is prepared to help people in case of any emergency, he said.