Al Jazeera's David Chater, reporting from Kabul, said there were a number of reasons for the vote's postponement.
"One, [the government] is $50m short of the $120m needed," he said.
"May 22 is the time when the large number of reinforcements come into this country announced by [US] President Obama.
"Thirty-seven thousand troops, 30,000 American and 7,000 Nato [troops] will be engaging Taliban in some of the fiercest battles seen so far.
"This is where they are going to win or lose this fight against the Taliban. Not the time to be having a parliamentary election."
The postponement removes a potential source of friction between Hamid Karzai, the newly re-elected president, and his Western backers just days before an international conference in London on Afghanistan's future on January 28.
Karzai's re-election on August 20, 2009, was largely characterised by fraud, widespread vote rigging, low voter turnout and a general lack of security.
William Crosbie, Canada's ambassador to Afghanistan, said it was important to address the deficiencies in the presidential election before holding another vote.
"We encourage the Afghan government and the Independent Election Commission to set the necessary conditions for parliamentary elections that are credible, secure and inclusive"
"We encourage the Afghan government and the Independent Election Commission to set the necessary conditions for parliamentary elections that are credible, secure and inclusive," he said in a statement.
Although the United Nations is holding tens of millions of dollars in an account to pay for elections in Afghanistan, diplomats have said that they cannot allow those funds to be released unless election reforms are carried out first.
Kai Eide, the senior UN representative in Afghanistan welcomed the delay, saying it gave the electoral institutions additional time to carry out the necessary preparations.
"This would have been extremely difficult to do by the original date," he said in a statement.
"It also provides time to make improvements to the electoral process based on lessons learned during the presidential and provincial council elections in 2009.
Meanwhile, a draft communique for the meeting in London has said that Afghan forces could begin to take control in some areas of the country by 2010.
The draft, a copy of which was obtained by the Reuters news agency on Sunday, says Afghanistan and the international community will agree to a "framework" for turning the country's security over to Afghan forces, with the process to begin this year.
It emphasises efforts to persuade Taliban fighters to lay down their arms, committing Afghanistan to set up an organisation to "reach out to insurgents", and international donors to pay for the programme.
Donors will also commit to channelling more of their aid through the Afghan government and providing debtrelief to Kabul, although precise figures were reportedly left blank in the draft.