"Idea (of proposing sunset clause for tax-holiday in SEZs is to accelerate investment," Chidambaram said to a question from the floor at a post-budget meeting with ASSOCHAM.

Otherwise investment may be promised and it may come during a long course of 20 years in these zones, Chidambaram said, adding that the sunset clause was imposed keeping in view political term of this government that ends in 2009.

Revenue secretary K M Chandrasekhar, on Friday had also justified the clause, saying it is a normal practice in any kind of fiscal concessions.

"The sunset clause is used for every exemption. It is part of any decision," Chandrasekhar had said on the sidelines of a post-budget meeting with PHDCCI.

The industry is up in arms against the budget proposal to end tax holiday for SEZ units from 2009 onwards, saying it was against the spirit of the proposed central legislation on these zones which is to be taken up by the cabinet after group of ministers finalised its recommendations.

Commerce minister Kamal Nath had sought prime minister Manmohan Singh's intervention to withdraw the budget proposal.

Nath expressed fear that it would act as a disincentive in promoting the fledgling SEZ aimed at boosting exports and employment