According to the UN rules, support of two-third member countries (129 nations) is required out of the total 193 member nations, Ms Swaraj said in the Lok Sabha during Question Hour.
Besides, all member nations will have to bear the cost of making Hindi one of the official languages of the UN.
"It is not difficult to get the support of two-third member nations. But when the issue of bearing the expenses comes, many small nations become hesitant which has led to a big hurdle in making Hindi an official languages of the UN," she said, adding that despite this, the efforts are on.
When a BJP member said that India has to pay Rs 40 crore as cost for making Hindi one of the languages in the UN, the minister the government is ready to pay "even Rs 400 crore if required" but the world body's rules does not allow to do so.
Congress MP Shashi Tharoor asked why India should make the effort to make Hindi as one of the languages in the UN as it is only India's official language and not the national language.
"If tomorrow someone from Tamil Nadu or from West Bengal becomes the Prime Minister, why should we force him to speak in Hindi at the UN," he said.
Mr Tharoor also said Hindi is official language of only one country - India.
However, Ms Swaraj countered Mr Tharoor saying he was unaware that Hindi is the official language of Fiji and is also spoken widely in Mauritius, Suriname, Trinidad and Tobago and many other countries.