The warning was made in a letter addressed to more than 60 nations as the Indian government, having survived a no confidence vote on Tuesday, dispatched diplomats to clear the deal with international regulators.
India must still negotiate a safeguards agreement with the International Atomic Energy Agency (IAEA), which has a board meeting on August 1, and obtain the blessing of the 45-nation Nuclear Suppliers' Group (NSG).
But Pakistan warned key members of the IAEA and the NSG in its letter that the safeguards agreement would impair non-proliferation efforts and "threatens to increase the chances of a nuclear arms race in the sub-continent".
India and Pakistan have fought three wars since they gained independence from Britain, and have been de facto nuclear weapons states since conducting tit-for-tat nuclear tests in 1998.
A peace process begun in 2004 has stabilised relations, but has made little progress on the most divisive issue -- the disputed region of Kashmir - and the two sides remain deeply distrustful of each other..
Mohammad Sadiq, a spokesman for Pakistan's Foreign Ministry, confirmed the contents of the letter, which he said was distributed to IAEA members in Vienna, but not released to the media.
"There are a number of questions about the deal, not only for Pakistan, but for many other countries," he told The Times.
"There should be a model agreement that could be signed with any country that meets the criteria. It should not be country-specific."
The US Congress must also approve the deal, which lifts a 34-year ban on selling US nuclear fuel and technology to India even though Delhi has refused to sign the Nuclear Non-Proliferation Treaty (NPT).
Indian and US officials say that all three steps could be completed in the next few months - although the White House has said that it could be pushed to get Congressional approval before President Bush steps down.
Meanwhile, the Indian government announced that it had sent its top diplomats to Germany, which holds the rotating chair of the NSG, and to Ireland, which has objections to the nuclear deal.
Ireland is one of the strongest proponents of the Nuclear Non-Proliferation Treaty, which was proposed by Frank Aiken, Irish Minister for External Affairs, in 1958.
The Nuclear Suppliers' Group - founded after India tested its first nuclear device in 1974 - is an informal grouping of 45 nuclear-exporting countries designed to prevent the proliferation of nuclear weapons and dual-use materials.
Its guidelines ban the export of nuclear fuel and technology to countries other than the five official "nuclear weapons states" - the United States, Russia, Britain, France and China - that do not have a specific agreement with the IAEA safeguarding their nuclear facilities.
India has submitted a draft safeguards agreement to the IAEA, under which it would separate its civilian and military nuclear facilities and allow IAEA inspections of the former.
But Pakistan said in its letter that the draft agreement had not listed the exact sites that would be safeguarded.
"What is the purposed of the Agreement if the facilities to be safeguarded are not known?" it asked.
Pakistan is not a member of the NSG, but it does sit on the current 35-member board of the IAEA - a United Nations agency - and is expected to vote against India's draft safeguards agreement at the August 1 meeting.
A two thirds majority is required to approve the agreement.
Among Pakistan's other objections are the date of the board meeting, which comes less than the required 45 days after a country starts circulating its draft.
The letter said that more time was needed because the agreement "is likely to set a precedent for other states which are not members of the NPT and have military nuclear programmes".
© 2008 Times Online