Prime Minister Manmohan Singh is likely to reshuffle his cabinet on Tuesday, informed sources have revealed.

Though there is no official announcement so far, the reshuffle is likely to take place at 5 p.m., the sources said. The Prime Minister's Office (PMO) has already told the Presidents's Office to make the preparations, they added.

Indications are that the 'Big Four' ministers - Finance Minister Pranab Mukherjee, Defence Minister A.K. Antony, Home Minister P. Chidambaram and External Affairs Minister S.M. Krishna - would not be affected in the reshuffle.

However, there will be promotions and inductions among the United Progressive Alliance (UPA) constituents. Congress is also expected to promote or induct ministers from poll-bound states like Uttar Pradesh, Punjab and Chhattisgarh, sources said.

Congress president Sonia Gandhi and Prime Minister Manmohan Singh met on Monday to give final touches to the new list, sources said.

This was their fourth meeting in three weeks.

The reshuffle comes in the wake of a series of corruption scams, which forced two ministers - A. Raja and Dayanidhi Maran - to quit office.

The reshuffle may see Dinesh Trivedi of the Trinamool Congress getting the railways portfolio, which was earlier held by West Bengal Chief Minister Mamata Banerjee.

Party leader Sudip Bandyopadhyay is also expected to be made a minister while Minister of State for Railways Mukul Roy may be given independent charge of shipping.

Congress sources said ministers from Uttar Pradesh like Beni Prasad Verma and Salman Khurshid may be moved to weightier ministries. Prasad is likely to be promoted to cabinet rank.

There is also speculation about actor-politician Raj Babbar, Lok Sabha member from Firozabad in Uttar Pradesh, being inducted as minister.

Punjab, another poll-bound state, may get a new minister - either Ravneet Singh or Manish Tewari.

Charan Das Mahant, MP from Korba in Chhattisgarh, may also find a berth in the council of ministers. Mahant is the only Congress member in the Lok Sabha from the Bharatiya Janata Party-ruled state.

Minister of State for Chemicals and Fertilisers Srikant Jena is likely to be promoted to cabinet rank to give proper representation to Orissa, according to party sources.

Sources said Law Minister M. Veerappa Moily may be shifted to human resource development ministry while Health Minister Ghulam Nabi Azad could be given charge of parliamentary affairs.

Rural Development and Panchayat Raj Minister Vilasrao Deshmukh may lose some of his portfolios, they added.

Azad, who has held charge of parliamentary affairs in the past, enjoys a good rapport with opposition leaders.

Political circles say it was unlikely that the DMK will name replacements for Raja and Maran, who resigned following allegations of involvement in the 2G spectrum scam.

However, there is speculation about induction of DMK spokesman E.K.S. Elangovan.

Some Congress ministers, including Murli Deora and B.K. Handique, who have offered to resign citing 'health reasons', and Kanti Lal Bhuria, who has been appointed the Madhya Pradesh party chief, are likely to be dropped, party sources said.

Minister for Statistics and Programme Implementation M.S. Gill may also be dropped.

Some of the young Congress ministers like Jyotiraditya Scindia, Sachin Pilot and R.P.N. Singh are also hopeful of promotions.

Muslim League Kerala State Committee nominee E. Ahamed has been lobbying for a promotion as a minister of state with independent charge, sources said.

A Congress leader said the reshuffle will give a 'makeover' to the scam-hit government and 'strengthen it to face the monsoon session of parliament' beginning on August 1.