Berhanu broke the course record when winning the Great North Run in 2004

The 25-year-old Ethiopian, who won the race two years ago, comes in after Tergat pulled out earlier this week.

Kenyan Tergat, 37, the race winner in 1991, told organisers that his training performances had been disappointing.

"Now that Tergat will be an absentee, it is building up into a much more open race," said the event's elite athletes director Matthew Turnbull.

"I wouldn't like to predict a winner."

Fellow Kenyan Rodgers Rop, who won the Boston and New York marathons in 2002, has also been confirmed in the field.

"Rodgers also took third place in the Great North Run before that triumph in New York, so like Berhanu, will not be entering into the unknown over the tough course," added Turnbull.

We respect Paul's wishes for not wanting to race when not fully prepared Great North Run elite athletes director Matthew Turnbull

Berhanu won the 2004 event in a time of 59.37, which was then the fastest half-marathon performance on British soil.

Last year, Berhanu finished runner-up to Zersenay Tadesse as the Eritrean lowered his record performance to 59.05.

Tergat's decision comes amid speculation that the reigning New York Marathon title holder is nearing retirement.

Speaking at an athletes' workshop in Nairobi last week, he said: "They say life begins at 40, but in athletics, that is when life ends.

"I am approaching (that age) and may soon be out of action."

Tergat was scheduled to face the reigning Olympic and world marathon champions Stefano Baldini of Italy and Jaouad Gharib from Morocco.

"We respect Paul's wishes for not wanting to race when not fully prepared," added Turnbull.

British number one Jon Brown, who is recovering from injury, is running in his first competitive race since the New York Marathon last November.

The Great North Run is the world's largest half-marathon event, with 50,000 entries.