Tony Worthington, the party's Northern Ireland education spokesperson, has also criticised the department's failure to expand nursery education and claimed the Government could lose the vote on the statutory Order to reorganise Ulster's local education authorities, the education and library boards.
He said he had mixed feelings about the Secretary of State's announcement last week that pre-school vouchers are to be postponed for a year in Northern Ireland. "I wanted vouchers to be scrapped and the money used to stimulate nursery education, but now we have lost the money, which is tragic. We will have to find other ways of increasing the number of nursery places," he said.
"We objected to vouchers because they were not targeted at social need but at relatively well-off people, and in a particularly bureaucratic and expensive way."
A consistent theme of the man who, with Labour's commanding lead in the opinion polls, is being increasingly seen as the province's minister-in-waiting, was criticism of the policy-making process in which, he argues "the minister does not find it necessary to explain what DENI (the Department for Education, Northern Ireland) is doing.
"DENI is not a rational department, whether it is dealing with vouchers, further education or the reorganisation of education and library boards. It does not make the case for any of its proposals. I am very disappointed at its lack of intellectual rigour in what they propose," he said.
"For example we have incorporation of further education without a word of why they are doing it or how it will help people who get little or nothing from education . . . It is simply a case of lifting English legislation without a word of explanation.
"If DENI is serious about targeting social need, it should say how it will help those who need a boost in their lives. The proposals for incorporation pose a huge threat to some of the providers outside the mainstream which are doing valuable work to help these people," Mr Worthington argued.
The Labour party will vote against the draft Order to reduce the number of education and library boards from five to three, Mr Worthington promised.
"The Government should be able to say where they are saving the money and why they are changing the boundaries. There is a contempt about the way it approaches policy-making."
He believes the Government could lose the vote since Northern Ireland parties, including the Conservatives' frequent allies, the Ulster Unionists, are also opposed to the changes in board administration.
On the long-running issue of selection at 11, Mr Worthington admitted candidly to internal tensions.
"I have no doubt that my kids got the better deal from going to comprehensive schools and I strongly support that system," he said. "But Labour puts emphasis on parental choice.
"Even most teacher unions, the strongest supporters of comprehensive education, agree they have not won the argument in Northern Ireland. We have got to win the argument on comprehensive education. We have to open up that area and conduct research into the impact of selection. Defenders say that because of selection Northern Ireland has more people reaching university level than the UK.
"I reject that. The reason Northern Ireland feels this pride is that it is better than England, but it is not better than Scotland, which has a fully comprehensive system. There are other reasons why Northern Ireland does relatively well, such as the investment in the quality of its teachers, far more so than in England."