Kolkata, Dec 20 (IANS): West Bengal's Mamata Banerjee ministry was expanded on Thursday with four new ministers joining in.

Governor K.N. Tripathi administered the oath of office and secrecy to the new joinees - Tapas Roy, Sujit Bose, Ratna Ghosh (Kar) and Nirmal Majhi, all ministers of state - at a ceremony at the Raj Bhavan where chief minister Banerjee, many of her cabinet colleagues, senior police and administrative officers, members of the diplomatic corps and Army officers were present.

The strength of the Banerjee ministry has now risen to 44.

Later, the ministers were allocated portfolios by the Chief Minister, with Roy being made the minister of state with independent charge of planning and parliamentary affairs.

Bose was named minister of state with independent charge of fire services, while Ratna Ghosh (Kar) would be the minister of state for MSME, and Nirmal Majhi the minister of state for labour, Banerjee announced after the swearing-in.

She also declared that Minister of State for Health Chandrima Bhattacharya would be given additional charge of the housing department.