By Simon Evans

MIAMI (Reuters) - FIFA has urged CONCACAF's rival factions to resolve their differences while the regional confederation's lawyer has warned ousted president Lisle Austin against taking court action.

In a letter to CONCACAF acting president Alfredo Hawit, seen by Reuters, FIFA general secretary Jerome Valcke said it was time for the infighting to end.

"We believe it is important that as Acting President, but also the CONCACAF Executive Committee and all relevant CONCACAF bodies, now focus on bringing back unity to CONCACAF. It goes without saying that FIFA is at your and CONCACAF's disposal should you need any assistance or advice," wrote Valcke.

Frenchman Valcke accepted the move to remove Barbadian Austin was valid but also reminded the confederation for North and Central America and the Caribbean that Austin should be given the chance to appeal.

"After a thorough analysis of the file in our possession, the bureau of the FIFA Legal Committee emphasised that the relevant steps and decisions taken within CONCACAF appear to be in line with the statutory provisions of CONCACAF.

"However, the bureau of the FIFA Legal Committee emphasised that all legal remedies must remain open to those who do not agree with any decisions taken against them, in line with the relevant articles of the CONCACAF statutes," wrote Valcke.

Austin has a hearing within CONCACAF set for July 13.

Insisting that he is the rightful president of the organization, Austin, who was in charge for just four days before being removed, has turned to the high court in Bahamas, where CONCACAF is legally domiciled as a 'not-for-profit corporation.'

On Friday, Austin declared he had won an injunction against the majority group which he said meant he could not be stopped from carrying out his role as acting president.

But CONCACAF's lawyer John Collins said Austin's move to regular courts breached CONCACAF and FIFA statutes and would lead to further sanction if the Barbadian did not cease.

"Mr. Austin's attempt to involve the ordinary courts is a clear violation of FIFA and CONCACAF's statutes and if he does not immediately take action to dismiss the court case, he may be subject to additional discipline by FIFA and CONCACAF," Collins told Reuters.

FIFA's statutes make clear that disputes should be settled within soccer's structures with the Court of Arbitration for Sport, in Lausanne, Switzerland, as the final arena for resolving disputes.

Warner was suspended by FIFA after allegations of bribery and pending further investigations by its ethics committee but no such charges have been made against Austin.

CONCACAF has declined to explain the detailed reason for Austin's removal, official documents referring only to an "apparent infringement" of statutes.

(Editing by Frank Pingue)