The assurance from government officials followed warnings that without serious engineering profession participation, the commission – which will judge infrastructure schemes of "national importance" such as airports, power stations, road and rail schemes – will lack credibility.
NCE launched a campaign last May to highlight the need for civil engineers to be at the centre of the infrastructure planning process after the IPC was proposed in the government's planning White Paper. It included a petition on the Downing Street website which closes on 8 December.
However, as the government published the Planning Bill this week, officials at the Department of Communities and Local Government (DCLG) assured NCE that civil engineers would be part of the IPC.
"We will need people from a range of backgrounds including civil engineers, planners, lawyers and people with environmental and community engagement expertise," said the DCLG spokesman.
"We are looking for a mix of expertise which will include people with a civil engineering background, but we are not going to have quotas saying we need two planners, two civil engineers, two lawyers and so on."
He added that civil engineering expertise could come from within the 70 strong IPC secretariat or be brought in when necessary.
The IPC will have 20 to 30 members that will be appointed by DCLG. From these members panels of three commissioners will be appointed to oversee the biggest infrastructure schemes. Individual commissioners will consider smaller schemes.
Some commissioners will be full time and the posts will be advertised nationally.
It is hoped that the new commission will be up and running by April 2009 and that it will consider 30 major infrastructure projects and 100 smaller projects of "national importance" each year. Savings of up to £4.8bn are predicted by 2030 by speeding up of major scheme delivery.
Under the legislation, the Secretary of State for Communities and Local Government will have the power to overrule the IPC and approve a scheme if, for example, national security is threatened.
National Policy Statements, on which major infrastructure is required, will be published by summer 2008. These will explain which schemes will be considered by the IPC and will cover energy, transport, water and waste disposal.
DCLG this week promised wide consultation and a debate in Parliament before publishing the statements, although there will be no vote to approve them.
Freight Transport Association Christopher Snelling head of rail freight and global supply chain policy said: "The current inefficient and cumbersome planning system is a major reason why, for example, Britain lacks the major port capacity it requires."
But the Campaign for Better Transport warned that the reforms would lead to more "direct action" against major schemes.
"The Government will put itself on a collision course with local communities, who may be left with no option but to resort to peaceful direct action," said campaigns director Jason Torrence.