SAM ALLARDYCE has stepped up his efforts to sign Czech Republic defender David Rozehnal after learning another of his top targets has moved to Chelsea.

While midfielder Joey Barton last night completed his move from Manchester City after Newcastle agreed to pay £300,000 extra, Allardyce had hoped Tal Ben Haim, the Israeli defender available on a free, would follow him to Tyneside.

However, Ben Haim penned a four-year deal with the Blues instead.

"The main focus was on Ben Haim and I did as much as I possibly could, but it looks like we have unfortunately lost out to Chelsea," said Allardyce.

"It's not my first frustration in the transfer market, we just don't publicise what we haven't got because I don't think that's right. We've made enquiries for players and if we've been knocked back we move on.

"The disappointment for me is how long I worked with Tal after bringing him into the Premiership three years ago. He was out of contract and he would have been good value. Everybody needs to pay what they can, we can't pay people the sort of money that is floating around all the time."

With Ben Haim now on the books at Stamford Bridge, Allardyce will step up his interest in other quality defenders.

A deal for Rozehnal remains pressing, with Newcastle continuing to hold negotiations with his French club Paris St Germain. Germans Borussia Dortmund, however, have revived their interest in the £2.5m defender.

Allardyce is determined to land at least two new centre-backs and, along with Rozehnal, Liverpool's Sami Hyypia and Marseille's Habib Beye remain serious candidates to arrive.

The Newcastle boss - who learnt that an agreement was reached with Manchester City over the sale of Barton - does not want to reveal the identities of further targets.

But he admits the middle of the defence is not the only area he is looking to strengthen. "The fact of the matter is, we don't have as many researched targets as we would have at Bolton because the scouting system we had there was very good," he said.

"But we scouted the players at Bolton that we could afford, some of the players we are looking at for Newcastle simply weren't in their price range."

Barton has been wrangling over a £300,000 payment from Manchester City that has delayed confirmation of his transfer to St James'.

And, after more than a week of dispute Newcastle concluded the deal - by paying the figure themselves. Instead of moving on for the £5.5m fee stipulated in his City contract, Newcastle have paid £5.8m instead.