A senior Iraqi spy has accused the prime minister, Nour al-Maliki, of handing out thousands of guns to tribal leaders in a bid to win votes. The claim was made by Iraqi National Intelligence Service former spokesman, Saad al-Alusi, a week before Iraq's general election, in which allegations of vote buying and exorbitant handouts have become widespread.

Maliki, who faces a bitterly contested final week of campaigning ahead of the7 March poll, has been photographed handing out guns to supporters in southern Iraq, engraved with a personal message from his office. However he denies that the delivery of weapons, along with cash payments, were improper.

Alusi, who was the INIS spokesman until he was asked to move to another ministry eight days ago, said some 8,000 guns were ordered from a Serbian supplier at the end of 2008 for use by intelligence officers. However he claimed Maliki "denied our contract at the last minute and made his own contract of 10,000 pistols, which he has used as election propaganda for himself and his party.

"This was a very important contract for the intelligence service. We have no weapons to this day," Alusi said.

A government spokesman, Ali al-Dabbagh, strongly denied the allegations: "These gifts have been given to the tribes for their contribution to security. They are not connected to the election campaign. The suggestion that anything has been taken away from other bodies to use for election purposes is wrong."

Alusi's remarks are an unprecedented challenge to the prime minister's re-election campaign from the spy service that has been considered closest to his government. Founded with CIA training and money, the INIS had been thought to be mostly independent and free of interference from Saddam Hussein's former regime, or from neighbouring states.

Tensions between Maliki's office and the INIS had been bubbling throughout last year, before boiling over in August when the INIS director, Muhammad al-Shahwani was sacked by Maliki's senior staff. Alusi claimed that around 190 employees had been sacked in recent weeks as tensions between the service and its political overlord spilled over into outright hostility.

"Those who did not implement the orders of the prime minister's office were forced out. Some of them were accused of being Ba'athists. They are 25 years old now and seven years ago they would have been 18 (and too young to be involved with the Ba'ath party). It is obvious this slur is being used to hang people by a sectarian government."

The head of Iraq's parliamentary integrity commission, Sheikh Sabah al-Sayedi, confirmed that guns have were handed out to community leaders and said his commission would ask Maliki to account for money the prime minister allegedly used from government coffers for his re-election campaign.

"He has given at least hundreds of them to tribal leaders in Amara, Nasireya, Diwaniya and many other provinces, Sayedi said. "They are American-made and arrived by the middle of 2009. It is a cheap way to buy votes. Saddam used to do the same. Maliki said he gave the guns out so that tribal leaders could protect themselves. So he wants to protect them and yet judges and lawyers die every day. What is the role of the Iraqi army and police? I hope the tribes will see through this."

Awda Ali, a member of the Nasireya council in Iraq's south confirmed that the prime minister had travelled to his area last week and handed out engraved weapons along with envelopes containing one million Iraqi dinars (£560) to leaders in the area. "He said it was in gratitude for their role in improving security."

Sheikh Nouri al-Dulaimi, a tribal leader in the restive Anbar province, which is not one of the prime minister's strongholds, said Maliki's deputy, Rafah al-Essawi, had visited the area last week with "10 million dinars". But we will not be bribed like this. I think Iraqis are more aware than they used to be."