Two House of Commons select committees have announced inquiries into controversial government plans to reform public services and change the rules on rail franchising.

The powerful public administration select committee is to examine the role of the private sector in delivering public services, while the transport committee is to consider rail franchising and funding of the rail network.

The public administration committee has announced its investigation into the involvement of private sector methods and personnel in the public sector will form part of a broader inquiry into public service reform.

With unions and Labour backbenchers expressing discontent about the government's plans to involve the private sector in the NHS and other key areas, the committee investigation is set to put the government on the spot over one of the most contentious policy areas during its second term.

The committee will consider whether the influence of business people working in Whitehall departments, task forces, local partnerships and other public services could threaten the public sector's traditional ethos and principles. The inquiry will also take in how public sector services can be more effectively delivered to their users.

Chairman of the committee Tony Wright, Labour MP for Cannock Chase, said that while there were potential benefits from using business methods and business people in improving public services, change could lead to the denigration of the performance and attitudes of public sector workers, and a fragmentation of responsibilities

"The danger is always that fundamental principles of public life get lost in the urge to deliver," he said.

Wright said the was a need to "keep vigilant" as the public and private sectors increasingly worked side by side in task forces to draw up policy options, local action zones and partnerships. He also pointed to the number of secondees who have senior roles in government departments.

"All this raises serious questions about accountability to the citizen, the role of public servants and the public service ethos, and I would like the Committee to explore them. I envisage that we would take evidence both from those who are involved in setting the policy framework and those in the public and private sectors who are engaged with these issues," added Wright.

The announcement of the investigation follows growing concern over the role of the private sector. A recent report by the Institute of Public Policy Research also argued that reforms were needed to improve the democratic accountability and effectiveness of the government's public private partnerships.

The inquiry will not, however, examine the financial details of the PPPs and other private finance initiative deals.

The transport sub-committee of the transport, local government and the regions committee, to which Gwyneth Dunwoody was re-elected as chairman despite the government's attempts to sack her, has decided to investigate the implications of the government's recent decision to switch from long-term contracts for rail franchises to short two-year extensions aimed at guaranteeing rapid improvements in standards.

The decision came under fire from train companies and is also at odds with the position of the Strategic Rail Authority, which has suggested that long-term planning should form the basis for the future of the rail industry.

The committee will consider whether the new approach will ensure rapid improvements, secure additional investment, and whether the government will need to increase rail funding given the events since the publication of its 10-year transport plan.

While the government was accused of "control freakery" in trying to remove two independent-minded MPs from the committees during the process of appointments, the new inquiries into two sensitive areas of government policy indicate that early attempts by the Commons to assert its independence from the executive seem set to continue.