India on Monday conveyed to China its unhappiness over the latter's move to block the Nuclear Suppliers Group waiver, but Beijing [Images] insisted that it played a "constructive" role at the 45-nation grouping's meeting in Vienna [Images] last week.

The Indian sentiments were conveyed by External Affairs Minister Pranab Mukherjee during his talks with his Chinese counterpart Yang Jeichi in Delhi [Images].

Sources said the Indian side raised the issue of the role played by China at the NSG meeting.

The Indian side said it was disappointed over China raising questions over grant of waiver to India particularly when the Chinese government had assured it at the highest levels that it will not be a "part of the problem" in the NSG meeting, the sources said.

Yang, on his part, said China did nothing to block the waiver and played a "construtive role" at the Vienna meeting.

China had joined six other countries, which had questions about non-proliferation issues at the NSG, compounding difficulties for India in securing the waiver.

The Chinese representative had expressed apprehensions that the waiver for India could affect the international non-proliferation system.

It was only after an intense push by the US and demarche issued by India in the wee hours of Saturday that China turned around to back the consensus for the waiver for New Delhi.

The NSG works by consensus and opposition by even one of the 45 member-countries could have scuttled the grant of exemption that will allow India to conduct civil nuclear trade with the international community.

India feels that China's act during the NSG meeting was not in keeping with growing relations between the two countries.

Indian government sources pointed out that the Chinese leadership, including President Hu Jintao, had assured Prime Minister Manmohan Singh [Images] and Mukherjee that Beijing would not create hurdles at the NSG.

Using the excuse of India waiver, China has apparently started batting for a similar exemption for Pakistan as it says that the NSG should "equally address the aspirations of all parties for the peaceful use of nuclear power while adhering to the nuclear non-proliferation mechanism."