Khartoum : South Sudan's army is building up its tank numbers at a time when tension is growing over a faltering peace deal with the north, the journal Jane's Defence Weekly reported on Wednesday, citing satellite evidence.

The southern Sudan People's Liberation Army (SPLA) on Tuesday said it was exercising its right to modernise its military hardware, but denied the reports of new tank deliveries, saying it had no intention of antagonising Khartoum.

Sudan's mostly Christian south won the right to keep its own army in a 2005 peace deal that ended more than two decades of civil war with the country's Muslim north.Relationships have remained strained and analysts have accused both sides of re-arming in preparation for potential flashpoints, including a referendum on southern secession.

The Jane's report comes at a particularly sensitive time, weeks away from a ruling on the contested boundaries of Abyei, an oil-producing region where both sides clashed last year.

"South Sudan is assembling an armour fleet, preparing for any eventuality in its enduring dispute with Khartoum," reported the latest edition of trade journal Jane's Defence Weekly.

"In total, military and diplomatic sources confirmed to Jane's, 100 MBTs (main battle tanks) were ordered by South Sudan."

The journal published satellite images it said showing an SPLA compound northeast of the south's capital Juba in March containing tanks covered with camouflage or "wedged into the vegetation around the compound".

Satellite images showed fresh track marks leading from Juba airport to the compound "indicating that these vehicles were airlifted to Sudan, probably in early May, and driven to the SPLA facility," said Jane's.

It added it had not been able to prove the vehicles pictured near Juba in May were the same T-72 tanks found on a Ukrainian ship hijacked by Somali pirates in September last year.

At the time, diplomats, the US navy and the pirates said they believed its cargo of tanks had been heading to south Sudan via Kenya. Both South Sudan and Kenya denied the claims.

The T-72 tanks were transported to Kenya in February, after a ransom was paid. Jane's said the Kenyan army had promised to show reporters the tanks were still there, but had so far not followed through on the offer.

The SPLA on Wednesday said it did order some T-72 tanks in 2007 but spokesman Malaak Ayuen Ajok denied receiving any more after that date.

"The SPLA has not received any new tanks this year. No tanks have been airlifted into South Sudan," he said.